Defending champion Garbine Muguruza, 2021 finalist Barbora Krejcikova and top seed Aryna Sabalenka were all eliminated from the Dubai Tennis Championships on Wednesday.

A day of upsets left Ons Jabeur, the eighth seed, as the top remaining player in the draw.

Some big names helped deliver the shocks, though, with world number two Sabalenka usurped by two-time Wimbledon champion and 2013 Dubai winner Petra Kvitova in straight sets.

Muguruza did not look like being one of the scalps as her title defence continued against Veronika Kudermetova.

But after taking the first set, the reigning WTA Tour Finals champion went down 3-6 6-4 6-4.

French Open champion Krejcikova, beaten by Muguruza in the final last year, also exited the tournament at the hands of Dayana Yastremska 6-3 7-6 (7-3).

Iga Swiatek let a set lead slip to Jelena Ostapenko, while two-time Dubai champion Elina Svitolina collapsed to lucky loser Jil Teichmann 7-6 (7-0) 6-2.

Jabeur, a winner against Jessica Pegula, was the only seed to win in a ruthless round of 16.

However, her reward in a still stacked quarter-final draw is a meeting with Simona Halep, another who has twice won in Dubai.

Top seed Aryna Sabalenka and defending champion Garbine Muguruza came through their first-round matches unscathed at the Dubai Tennis Championships on Tuesday.

Belarusian Sabalenka made light work of 19-year-old Marta Kostyuk, sealing a 6-4 6-1 win in one hour and 15 minutes.

Standing in her way of a third consecutive quarter-final in Dubai is Petra Kvitova, who beat Camila Giorgi on Monday.

Last year's champion and fourth seed Muguruza began her title defence with a 7-6 (7-5) 2-6 6-2 win over Czech qualifier Katerina Siniakova in two hours and 24 minutes.

Spaniard Muguruza will face Veronika Kudermetova in the second round after the Russian beat former world number one Victoria Azarenka in straight sets earlier on Tuesday.

There were also wins for eighth seed Ons Jabeur and 10th seed Elina Svitolina against Vera Zvonareva and Mayar Sherif respectively.

Elsewhere, there was a shock as qualifier Elena-Gabriela Ruse dumped out third seed Paula Badosa 6-3 5-7 6-4.

Ninth seed Danielle Collins is also out after the American retired due to dizziness in the second set against Marketa Vondrousova.

Sofia Kenin failed to put up a fight as she went down 6-1 6-2 to Jelena Ostapenko.

Alize Cornet is simply living in the moment at the Australian Open, after she suggested 2022 will be her final year on the court.

Cornet defeated reigning WTA Finals champion Garbine Muguruza 6-3 6-3 on Thursday to reach the third round of the Australian Open for the sixth time in her career.

The 31-year-old did not offer up a single break point across the 87-minute encounter with 2020 Australian Open finalist Muguruza, who entered the tournament ranked third in the world.

It marked Cornet's third straight win over Spain's Muguruza, who is a two-time grand slam champion.

Cornet is playing in her 63rd grand slam and 17th Australian Open, yet the Frenchwoman has never progressed deeper than the fourth round at a major.

This is Cornet's 60th successive appearance in the main draw at a grand slam, meaning she is just two shy of the record held by Ai Sugiyama (62).

Should Cornet, who will play Tamara Zidansek in round three, feature in the main draw of each of this year's majors, she will set the outright record.

However, should she achieve that feat, it may well mark the end of her career.

"I'm telling myself that I'm playing probably my last year. I'm not sure yet," she told reporters.

"When I stepped on the court, I was like, You know what, just enjoy the moment because you don't know if you're going to come back. I think that's what made the difference.

"Playing a whole year, playing 100 per cent, trying to beat this record of consecutive play in a grand slam. After that, I think it will be a good time for me to retire. 

"I gave so much to this game and to this tennis life. I feel I'm pretty much ready for the next chapter.

"It's been a while [since I] beat a Top 5 player in a slam, so it's a really good feeling. 

"I really enjoyed it today, which doesn't mean I will enjoy it tomorrow! That's why when the fun is here, you have to take it. You never know how you're going to feel in the next match."

Muguruza was not the only big name to drop out on Thursday, with sixth seed Anett Kontaveit falling foul of teenager Clara Tauson.

The 19-year-old Dane needed just 79 minutes to seal a 6-2 6-4 victory that brings up her first win over a Top 10 opponent in only her second such match.

Kontaveit won 28 of her last 32 matches in 2021 to break into the Top 10.

"It's the first time I'm in the third round of a slam," said Tauson. 

"Playing a player like her to reach it, it's a really big achievement for me. Obviously, it was one of the things I really wanted to do, to beat the good players in the bigger tournaments.

"Doing it in a slam is a really great feeling. It's just a lot of hard work that I've put into it."

The tennis season has begun with Rafael Nadal, Ash Barty, Paula Badosa and Thanasi Kokkinakis among the champions at small-scale events in Australia.

Yet there has been one dominant story in the sport and little else has had a look-in in the lead-up to the Australian Open.

Now that Novak Djokovic knows his fate, there is the welcome prospect of eyes turning to matters on the tennis court, rather than the Federal Court.

With the action getting under way in Melbourne on Monday, Stats Perform looks at the main protagonists and what the numbers tell us about another high-stakes grand slam.

Djokovic absence blows open men's draw

As defending champion Djokovic heads for home, it is worth a reminder of how he has dominated this tournament.

Nine of his grand slam titles have come in Melbourne, and he has taken the trophy in each of the last three years, helping him cosy up alongside Roger Federer and Rafael Nadal on 20 majors, an all-time record they share. Of the 'Big Three', only Nadal is in the draw this year, with Federer currently on the injured list.

Djokovic has the highest win percentage in the Open Era (since 1969) at the Australian Open, among players with 20 or more wins (91.1 per cent – W82 L8). He was hoping to join Nadal (13 French Opens) and Margaret Court (11 Australian Opens) in the exclusive club of players to reach double figures for singles titles at one slam.

The Serb was also aspiring to become the first man in the Open Era to win four consecutive Australian Opens. It happened once before the tour turned professional, with Roy Emerson winning five in a row from 1963 to 1967. Djokovic has left Melbourne with the title every time that he has made it through to the semi-finals.

So who takes the title now?

Only Bjorn Borg (89.2 per cent) has a higher winning percentage in grand slam matches than Nadal (87.7 per cent) and Djokovic (87.5 per cent) in the Open Era, among players with 100 or more wins. So why not Nadal?

The 35-year-old and Djokovic have carved up 12 of the last 14 grand slam titles, Nadal winning four of those (three French Opens, one US Open). He is battling back from a foot injury lay-off and coronavirus, and might need to get the early rounds out of the way without undue stress to stand a chance at the business end.

The two exceptions in the Nadal-Djokovic sequence of slam dominance have come at the US Open, with Dominic Thiem winning in New York in 2020 and Daniil Medvedev triumphing at Djokovic's expense in last year's Flushing Meadows final. Thiem is not in Australia, but world number two Medvedev is, looking to become the third Russian man to win two slams, after Yevgeny Kafelnikov and Marat Safin.

The last man other than Federer, Nadal and Djokovic to secure back-to-back slam singles title was Andre Agassi (US Open 1999 and Australian Open 2000), but that is Medvedev's objective now, and he has the game to pull it off.

Nadal has reached at least the quarter-final stage in 15 of his last 16 grand slam appearances, winning six of those majors (four French Opens and two US Opens), so he may well be a factor.

Who else is in the frame? Alexander Zverev probably, having reached the quarter-finals in Australia in the last two seasons (SF in 2020 and QF in 2021). He won the Olympic Games and ATP Finals titles last year, so a grand slam is an obvious next step. He might want to keep double faults in check though, having served a tour-high 113 in slams last season.

Stefanos Tsitsipas reached the Australian semi-finals in 2019 and 2021, so throw him into the mix too, and Matteo Berrettini might be a threat. The Italian, a runner-up to Djokovic at Wimbledon in July, served more aces than any other player in grand slams last year (311 aces, 16.4 on average per match).

Others have more modest ambitions

Andy Murray is back at the Australian Open for the first time since 2019, when he lost in the first round against Roberto Bautista Agut in five sets and was more or less given his last rites as a tennis pro after the match, having indicated he was close to retirement.

The five-time Australian Open runner-up last won a match in this tournament in 2017, when he reached round four. A tough opener against Nikoloz Basilashvili awaits.

Spanish 40-year-old Feliciano Lopez will make his 80th appearance in a grand slam and become the second man in the Open Era with 80 or more appearances at the four majors, after Federer (81).

Do not expect an Australian to be men's champion, by the way. The last time an Australian reached the men's singles final was 2005, when Lleyton Hewitt lost against Safin, and the last home champion was Mark Edmondson in 1976.

Barty backed in stacked women's draw

For the first time since 1997, neither Serena nor Venus Williams will take part in the Australian Open. Yet the women's tour is in rude health, even without those great bastions.

Ash Barty is world number one and a standout pick for many, only enhancing her claims after winning an Adelaide International title in the run-up to this fortnight.

But there is staggering depth on the women's side at present, and Barty will face stiff competition.

Incredibly, the last five grand slam finals have featured 10 different women, and teenager Emma Raducanu's against-all-odds US Open triumph in September shows best of all that new stars are emerging.

Yet since 2000, only three non-seeded players have reached the women's singles final at the Australian Open: Serena Williams in 2007, Justine Henin in 2010 and Garbine Muguruza in 2020. 

Barty could become the first Australian to be women's champion since Chris O'Neil in 1978, and the first to reach the final since Wendy Turnbull lost to Hana Mandlikova in 1980.

The Queenslander is the top seed, and the last time the number one failed to reach at least the fourth round at Melbourne Park was in 1979, when Virginia Ruzici lost her opening match. Barty ended a long wait for an Australian winner of the women's title at Wimbledon last year, so why not closer to home as well?

Naomi Osaka is back, so what should we expect?

Truth be told, that's hard to know. Osaka took time out from tennis after the US Open to focus on her mental health and enjoyed hanging out with friends, before deciding she missed tennis enough to go back on tour.

She had three wins at the Melbourne Summer Set tournament recently before withdrawing from a fourth match, saying her body had "got a shock" from the intensity. As defending champion in the season's first major, she has a target on her back and will need to find a way to handle that.

Over the past six seasons, only Osaka has managed to win back-to-back grand slam singles titles among the women, and she has done so twice (US Open 2018 and Australian Open 2019, plus US Open 2020 and Australian Open 2021).

The last player to win back-to-back women's Australian Open singles titles was Victoria Azarenka (2012 and 2013), so it does not happen regularly.

Osaka has an 85 per cent win rate at this tournament: since 2000, only Jennifer Capriati (90 per cent) and Serena Williams (89 per cent) have had a higher win percentage in the main draw.

You want challengers to the big two? Try sticking a pin in the draw

The Daphne Akhurst Memorial Cup, which goes to the champion, is a trophy that upwards of a dozen women will seriously believe they can win.

Aryna Sabalenka has reached the semi-finals of the last two slams but is mired in some kind of hellish serving groove, having made 74 double faults in her last four matches and lost the last three in a row.

Anett Kontaveit won a tour-high 39 matches on hard courts last year but has only been to one grand slam quarter-final – last year in Australia, losing to Simona Halep.

What about Ons Jabeur, who matched Kontaveit for a tour-high 48 wins across all surfaces last year? The Tunisian is queen of the drop shot, making 147 successful such plays on tour last year, more than any other player, and recently reached the top 10 in the WTA rankings for the first time.

Maria Sakkari reached two slam semi-finals last year, the first of her career, and the form of Barbora Krejcikova and Badosa in the past week in Melbourne marks them out as contenders. Both are recent fast-risers, Krejcikova already with a French Open title to show.

WTA Finals champion Muguruza could be the second Spaniard to twice reach the Melbourne title match, after Arantxa Sanchez Vicario (1994 v Steffi Graf and 1995 v Mary Pierce). Spain has never had an Australian Open women's singles winner: former French Open and Wimbledon champ Muguruza is an authentic contender.

Halep was runner-up to Caroline Wozniacki in 2018, a semi-finalist in 2020 and quarter-finalist last year, and a Melbourne Summer Set title was a handy warm-up for the Romanian. Consider her, too.

Monica Seles, in 1991, was the last player to triumph on her debut in the main draw, but she was already a grand slam winner (1990 French Open). Given the strength of the line-up, the prospect of a bolter coming through this field is unlikely, even if the example of Raducanu tells us anything is possible.

Daria Kasatkina reached her second semi-final in as many weeks with a straight-sets victory over Garbine Muguruza at the Sydney Tennis Classic on Wednesday.

The world number 26, who was defeated by Amanda Anisimova in the Melbourne Summer Set 2 semi-finals last week, beat second seed Muguruza 6-4 6-4.

Kasatkina held throughout the opening set, landing 67 per cent of her first serves, and saw the job through in the second despite a couple of early breaks for Muguruza.

It is the Russian's first win over a top-five opponent since beating Caroline Wozniacki at the 2018 French Open.

She will now face fifth seed Paula Badosa, who saw off Olympic gold medallist Belinda Bencic 7-6 (8-6) 3-6 6-3 in an entertaining match lasting two hours and 35 minutes.

The other semi-final in Sydney will be contested between Anett Kontaveit and Barbora Krejcikova, who advanced past Ons Jabeur and Caroline Garcia respectively.

Krejcikova proved far too strong for Garcia, prevailing 6-0 6-2 in 70 minutes, while Kontaveit was in action for just 43 minutes before being handed a walkover win in her match.

Jabeur had targeted "payback" against Kontaveit after her quarter-final opponent pipped her to the final WTA Finals spot in November, but injury cost her the chance to do so.

Having lost the first set 6-4, Jabeur – who eliminated Petra Kvitova in the previous round – felt unable to continue due to a lower back injury.

At the Adelaide International 2, three of the five Americans in action made it through to the semi-finals.

Alison Riske's clash with compatriot Madison Brengle ended early due to the latter retiring with the first set level at 3-3. Tamara Zidansek awaits Riske after beating Lauren Davis 7-6 (7-4) 7-6 (9-7).

Coco Gauff and Madison Keys will meet in the other semi-final, meanwhile, following victories over Ana Konjuh and Ludmilla Samsonova in two and three sets respectively.

Ons Jabeur eliminated Petra Kvitova from the Sydney Tennis Classic and immediately set her sights on "payback" against next opponent Anett Kontaveit.

World number 10 Jabeur had lost her previous four meetings with Kvitova, but she emerged victorious on Wednesday with a 6-4 6-4 win to reach the quarter-finals.

Jabeur recovered from 3-1 down in both sets at Ken Rosewall Arena and converted half of her six break points on her way to setting up a meeting with Kontaveit.

The two will resume their friendly rivalry after Kontaveit overcame Romanian qualifier Elena-Gabriela Ruse 6-3 6-1.

Jabeur lost out to Kontaveit for the last WTA Finals spot in November and is now seeking revenge in the final warm-up event ahead of the Australian Open.

"Anett is a great player. We had our moments last year," Jabeur said. "I told her, 'You're obsessed with me, you always follow me, so stop [smiling]'.

"I know the pressure is on me, not really on her. But maybe I can get some payback for last year."

Garbine Muguruza is also through to the last eight in Sydney thanks to a 6-1 7-6 (7-4) win against Ekaterina Alexandrova.

The two-time major champion will face Daria Kasatkina, who beat Elise Mertens 6-3 6-4, for a place in the semi-finals.

Third seed Barbora Krejcikova survived a brief fightback from Jaqueline Cristian to advance 6-1 7-5, meanwhile, and Paula Badosa beat home hope Ajla Tomljanovic 6-3 6-4.

There was disappointment for in-form Elena Rybakina, who thrashed Emma Raducanu on Tuesday but had to withdraw from her clash with Caroline Garcia with a thigh injury.

At the Adelaide International 2, Coco Gauff prevailed 6-3 5-7 6-3 in her battle of the teenagers showdown with Marta Kostyuk.

Gauff is one of five Americans in the quarter-finals along with Madison Brengle, Alison Riske, Lauren Davis and Madison Keys, who beat Tereza Martincova 6-1 6-3 to advance.

World number one Ash Barty will start her 2022 season at the Adelaide International along with eight of the other current 10 top players in the world.

Barty has held top spot in the women's rankings since September 2019 and collected five titles – including Wimbledon – in the 2021 season but missed the French Open with a hip injury.

She also opted to not play in the season-ending WTA Finals in Mexico due to coronavirus-enforced quarantine concerns that could disrupt her preparation for the following campaign.

The Women's Tennis Association (WTA) confirmed on Friday that Barty would begin her 2022 season in Adelaide on January 2, along with defending champion Iga Swiatek, WTA Finals victor Garbine Muguruza and Roland Garros winner Barbora Krejcikova, as the world's elite players prepare for the Australian Open.

The entry list for the WTA 500 tournaments also includes Tokyo Olympics gold medallist Barbara Bencic, who finished runner-up to Swiatek in 2021, former world number one Karolina Pliskova and US Open runner-up Leylah Fernandez.

The field boasts 12 major trophies between them, but three grand slam winners will kick-start their seasons in Melbourne the day after.

Naomi Osaka, who is aiming to defend her title at the Australian Open, gets her preparations underway in the Melbourne Summer Set.

Two-time major winner Simona Halep and reigning US Open champion Emma Raducanu will play in the Melbourne Summer Set.

The trio are among 20 of the top 50 ranked players in the world for the two WTA 250 tournaments starting on January 3, with the entry list split between the competitions the week before matches start.

Raducanu will feature in just her eighth Tour-level event, and her fourth tournament since winning her first major, while Osaka will be appearing for the first time since an early defeat in the third round of the US Open to Fernandez.

Now, Muguruza – at the age of 28 – is the oldest year-end champion since Serena Williams seven years ago and is up to third in the rankings.

For Muguruza it was never a question of if she had the game to be back among the elite players, merely just the need to prove so.

"I'm just very happy I proved to myself once again I can be the best, I can be the 'maestra,' like how we say in Spanish," Muguruza said. "That puts me in a very good position for next year, a good ranking.

"The last couple of years, I didn't play the same way I played before. But I didn't play bad tennis, either. 

"I was just here, there, not going into the deep rounds at grand slams that made the difference. I always felt I had the tennis. I was just not putting the battle together.

"I always believe I [could make] finals of a grand slam, [climb] the rankings, I'm like 'I have the tennis, I just have to show it'. It's hard, of course."

Now, Muguruza – at the age of 28 – is the oldest year-end champion since Serena Williams seven years ago and is up to third in the rankings.

For Muguruza it was never a question of if she had the game to be back among the elite players, merely just the need to prove so.

"I'm just very happy I proved to myself once again I can be the best, I can be the 'maestra,' like how we say in Spanish," Muguruza said. "That puts me in a very good position for next year, a good ranking.

"The last couple of years, I didn't play the same way I played before. But I didn't play bad tennis, either. 

"I was just here, there, not going into the deep rounds at grand slams that made the difference. I always felt I had the tennis. I was just not putting the battle together.

"I always believe I [could make] finals of a grand slam, [climb] the rankings, I'm like 'I have the tennis, I just have to show it'. It's hard, of course."

Garbine Muguruza became the first Spaniard to win the WTA Finals after defeating Anett Kontaveit 6-3 7-5 in a history-making victory.

Arantxa Sanchez Vicario was the only other player from Spain to reach the WTA Finals decider, finishing runner-up to Stefanie Graf in 1993.

But Muguruza exceeded that result as the former world number one proved too strong for Kontaveit at the prestigious year-ending championship on Wednesday.

Muguruza – a two-time grand slam champion – also celebrated her 10th WTA Tour title, having been the only player to beat Kontaveit within the last month following her group-stage success in Guadalajara.

After exchanging breaks in the opening set, Muguruza struck for a 4-3 lead, winning the last four games to seize control midweek.

Kontaveit claimed the early break in the second set as errors started to mount for Muguruza, who eventually found herself 5-3 adrift.

But as Kontaveit served for the set, Muguruza rallied in a dominant display, reeling off four consecutive games like she did in the opener to take home the WTA crown.

WINNERS/UNFORCED ERRORS 

Kontaveit – 15/39
Muguruza – 16/25

ACES/DOUBLE FAULTS 

Kontaveit – 3/6
Muguruza – 2/0

BREAK POINTS WON 

Kontaveit – 2/4
Muguruza – 5/11

Anett Kontaveit will face two-time grand slam champion Garbine Muguruza in the WTA Finals decider after outlasting Maria Sakkari 6-1 3-6 6-3.

Kontaveit – the most in-form player on the WTA Tour – was pushed by fourth seed Sakkari in Tuesday's semi-final at the year-ending championship but fought hard to reach the biggest final of her career.

Having entered the Guadalajara showpiece on the back of three titles and 19 wins in 20 matches, eighth-seeded Estonian star Kontaveit maintained her momentum with her Tour-leading 48th win of the season.

Kontaveit will now go head-to-head with former world number one and sixth seed Muguruza in a repeat of their group-stage meeting, which the latter claimed in straight sets.

The first set was straightforward for Kontaveit, who broke twice as she dominated on serve against Greece's Sakkari.

But Sakkari – who trumped Aryna Sabalenka to reach the semi-finals at the expense of the top seed – remained composed, breaking at the end of the second set to force a decider.

After trading breaks early in the third, Kontaveit eventually prevailed as she looks to avenge her loss to Muguruza in Wednesday's title showdown.

Kontaveit is now a perfect 7-0 in semi-finals this year and the 25-year-old WTA Finals debutant stands on the cusp of a third straight trophy and fifth overall, which would tie world number one Ash Barty for the most this year.

WINNERS/UNFORCED ERRORS 

Kontaveit – 26/33
Sakkari – 15/32

ACES/DOUBLE FAULTS 

Kontaveit – 6/3
Sakkari – 9/3

BREAK POINTS WON 

Kontaveit – 4/8
Sakkari – 2/2

Karolina Pliskova continued her dominance against Garbine Muguruza with an epic three-set win at the WTA Finals.

Pliskova outlasted former world number one Muguruza 4-6 6-2 7-6 (8-6) as the year-ending WTA Finals got underway in Guadalajara on Wednesday.

The first WTA Finals hosted in Latin America, third seed Pliskova prevailed in a third-set tie-break for her ninth victory over two-time grand slam champion Muguruza – her best professional record against an opponent on Tour.

After a slow start, sixth seed and Spanish star Muguruza finished strongly to claim the opening set of the Group Teotihuacan contest under the Guadalajara lights midweek.

Pliskova – the most experienced player in this year's field with her fourth consecutive Finals appearance – raced out to a 3-0 lead in the second set and it was an advantage she never relinquished.

The pair went toe-to-toe in the final set as a tie-break loomed after Muguruza saved two match points in the 10th game.

Pliskova, however, was not to be denied as Muguruza lost a third-set tie-break on hard courts for the first time since January 2014.

WINNERS/UNFORCED ERRORS

Pliskova – 
Muguruza – 

ACES/DOUBLE FAULTS

Pliskova – 8/9
Muguruza – 8/3

BREAK POINTS WON

Pliskova – 20/34
Muguruza – 23/33

The 2021 WTA Finals look set to be a fitting end to a fascinating season on the Tour.

The 50th year-ending championships, which will take place in Guadalajara instead of Shenzhen due to coronavirus restrictions, will see eight of the top-10 ranked players come together in two round-robin groups, with four semi-final places up for grabs.

Six of the eight competitors will make their debuts at the event, while only two grand slam finalists from this year – and just one champion – will be present. With world number one Ash Barty withdrawing because of concerns around possible quarantine issues, it really does feel like an open draw.

Stats Perform looks at the eight Finalists and the key data you need to know before the action gets underway...

Group Chichen Itza

Aryna Sabalenka (1)

World number two Sabalenka is the top-ranked competitor in Guadalajara, with 44 match wins this year and titles in Abu Dhabi and Madrid, where she beat Barty.

The Belarusian boasts formidable weapons: Sabalenka has won 71.1 per cent of first-serve points and has an average of 8.4 forehand winners per match on the Tour this season, both of which are best figures among the eight Finalists.

She has only played two matches since losing to Leylah Fernandez in the US Open semi-finals, though, both of which were at last month's Kremlin Cup in Moscow.

Did you know? Since the start of 2018, Sabalenka has won the joint-most matches (three) in WTA Tour main draws after losing the first set 0-6. At the same time, she is 9-13 in three-set contests in 2021.

Maria Sakkari (4)

The nearly-woman of 2021, Sakkari has reached more semi-finals this year (seven) than anyone else on the WTA Tour, including at two of the four slams, but made it to just one final (in Ostrava, where she lost to Anett Kontaveit).

Still, this has been a historic year for the 26-year-old, who became the first Greek woman to reach a major semi-final, enter the top 10 and qualify for the season-ending championship.

Since the start of the US Open, Sakkari has lost only four of 14 matches, a run that includes the semi-final of the Kremlin Cup where she retired due to dizziness.

Did you know? Nobody has won more Tour-level matches against top-10 opponents this year than Sakkari (seven, level with Barty and Jessica Pegula). Before 2021, her record in such matches was 10-13.

Iga Swiatek (5)

Swiatek, the 2020 French Open champion, is the youngest competitor at these Finals at 20 years and 170 days old (as of the tournament's end). She is just the second player born this century to reach this event, after Bianca Andreescu in 2019.

Although unable to get beyond the quarter-finals of a major this year, Swiatek did win titles in Adelaide and Rome, where she inflicted a double bagel on Karolina Pliskova in the final.

Her success in Australia was her first on a hard court, a surface on which she won 19 of 28 matches this year.

Did you know? Swiatek has won 58 per cent (28 of 48) of her matches this season in straight sets, the highest ratio among the Finalists.

Paula Badosa (7)

A successful year for Badosa has been built on clay: she won a Tour-leading 17 matches on the dirt in 2021, reaching the French Open quarter-finals, the last four in Madrid and Charleston and winning the title in Belgrade.

This has been a breakthrough season for the 23-year-old across all surfaces, though, one that culminated in a record-breaking three-set win over Victoria Azarenka in the final at Indian Wells last month.

Badosa clinched that match after a third-set tie-break. She has won four deciding sets in that fashion this year, the most of anyone on the WTA Tour.

Did you know? Badosa has won seven matches (excluding the Olympics) after dropping the first set in 2021. Nobody else has as many come-from-behind victories among the Finalists.

Group Teotihuacan

Barbora Krejcikova (2)

The only major singles champion from 2021 at these Finals, Krejcikova has enjoyed a remarkable rise this year.

Along with success at Roland Garros, where she also triumphed in the doubles, the Czech won titles in Strasbourg and Prague; only world number one Barty (five) and Kontaveit (four) have won more this year.

Among the eight finalists, Krejcikova boasts the highest break-point conversion ratio (49.7 per cent, or 142/286) and break-point saved figure (66.4 per cent, or 150/226) for this season. She has become a clutch competitor and will be hard to stop in Mexico, both in the singles and the doubles.

Did you know? Krejcikova has won six matches against top-20 opponents in her career. All six of those wins were in 2021.

Karolina Pliskova (3)

Pliskova boasts impressive experience of the year-ending event: she is only the fourth player to qualify for five or more WTA Finals since the current format was introduced in 2003 (after Agnieszka Radwanska, Petra Kvitova and Azarenka).

Beaten in her three Tour finals this year, including Wimbledon, the 29-year-old will be desperate to go at least one better than her three consecutive semi-final appearances at this event.

Pliskova begins against Garbine Muguruza, a player she has beaten twice before at the season-ending tournament.

Did you know? Pliskova leads the Tour for aces this season with 364, hitting a year-best 21 in her round-of-16 match with Jelena Ostapenko in Stuttgart. It's the fourth time in the past six seasons Pliskova has been top of the aces standings.

Garbine Muguruza (6)

This is the first time since 2000 that two Spanish players have contested the Finals. Back then, it was Conchita Martinez and Arantxa Sanchez Vicario at Madison Square Garden in New York.

Muguruza, champion in Dubai and Chicago this year, has won more matches on hard courts (34) than anyone else in 2021 aside from Kontaveit. She also boasts the best average for successful net approaches this year (3.0) among the Finalists, which will make her a challenging obstacle in what will be her first Finals since 2017.

The former world number won made a career-high four Tour finals this year and won more than one trophy in a season for just the second time, sending her back into the top 10 for the first time since 2018. 

Did you know? Muguruza boasts a 10-1 record in WTA tournaments in Mexico, winning back-to-back titles in Monterrey in 2018 and 2019.

Anett Kontaveit (8)

With a Tour-leading 37 hard-court wins this year and on a formidable run of form, Kontaveit could spring a surprise at her first Finals.

After losing her fifth match in a row to Ons Jabeur on August 17, the Estonian went on a run of 26 wins from 28 matches, lifted four titles and broke into the top 10 for the first time. It was Jabeur she edged out for a place at this tournament after she won her fourth title of the year at Cluj-Napoca.

Along with Barty, Kontaveit is the only player to reach six Tour-level finals this year, while nobody at the season-ending tournament has won more titles (four).

Did you know? Kontaveit has hit the most backhand winners (293) on hard courts on the WTA Tour in 2021, averaging nearly six per match.

Maria Sakkari admitted she got twitchy before finishing off Simona Halep to reach the Kremlin Cup semi-finals.

The Greek star is chasing what would be just her second career title at WTA level, but the limited silverware belies her growing reputation: Sakkari has shot up to a career-high seventh in the world rankings during her best season on tour.

Looking to finish with a flourish, both in Moscow and next month at the season-ending WTA Finals, Sakkari scored a 6-4 6-4 victory over former world number one Halep on Friday.

The victory sets up a last-four clash with Ekaterina Alexandrova, after the Russian impressed a home crowd by landing a 6-3 6-4 win against top seed Aryna Sabalenka.

Yet Sakkari was almost reeled in by Halep from the point of victory in the second set, being unable to finish off the match on her own serve after building a 5-1 lead. Halep twice broke back, before dropping her own serve.

"It was a very tough match today," Sakkari said in an on-court interview. "It was the first time I'd played Simona, but I knew what to expect: she makes a lot of balls, more than any other player. I had a tough moment in the second set when I was 5-1 up, but finally, I found a way. I got a little nervous, a little bit tired.

"The last couple of months have been tough, I've been travelling a lot so haven't recovered enough. I just tried harder in the last game and just went for it."

Alexandrova's shock win over Sabalenka gave her a sixth career victory over a top-10 player. Second seed Garbine Muguruza followed Sabalenka out of the tournament, walloped 6-1 6-1 by in-form Estonian Anett Kontaveit, who has won 19 of her last 21 matches on tour, including beating Sakkari in the Ostrava final last month.

Kontaveit's semi-final opponent at the WTA 500 event will be Marketa Vondrousova, who claimed a 6-4 6-2 win over Anastasia Pavlyuchenkova.

At the Tenerife Open, Italian Camila Giorgi is the only seeded survivor in the semi-finals. The Italian fourth seed saw off Arantxa Rus 6-1 6-1, with Frenchwoman Alize Cornet and American Ann Li also among Friday's winners at the WTA 250 tournament.

Aryna Sabalenka edged past Ajla Tomljanovic in the Kremlin Cup to reach the quarter-finals in her first match since contracting COVID-19 after the US Open semi-finals. 

Top seed Sabalenka – appearing in Moscow for the first time – had not played since being downed by Leylah Fernandez, having tested positive for coronavirus on the eve of the Indian Wells Open. 

The Belarusian, who sits second in the world rankings, profited from a bye in the first round before battling past Tomljanovic 7-6 (7-2) 4-6 6-1 on Wednesday as she fired 10 aces but made 30 unforced errors. 

Sabalenka will now meet Ekaterina Alexandrova after the Russian cruised past Anhelina Kalinina 6-4 6-1, while Anastasia Pavlyuchenkova comfortably defeated Bernarda Pera 6-2 7-5. 

Number two seed Garbine Muguruza also reached her seventh quarter-final of the season as she defeated Tereza Martincova 6-4 4-6 6-3 in just under three hours in Moscow. 

Meanwhile, Elina Svitolina was shocked in the Tenerife Open as she was dumped out by Maria Camila Osorio Serrano, who succeeded 5-7 6-3 6-2 to claim her first top-10 victory. 

Svitolina was the favourite in Spain and comfortably took the first set on Tuesday. However, inadequate light stopped play and the 19-year-old Osorio responded emphatically the following day to secure a memorable triumph. 

Ann Li coasted past Varvara Gracheva 6-4 6-2 after Anna Karolina Schmiedlova had dispatched Jaqueline Cristian 6-2 7-5 in the opening match of the day. 

Xinyu Wang retired injured against Alize Cornet, who led 4-1 in the decisive set, while Donna Vekic and Irina-Camelia Begu's match was suspended for bad light with the Croatian leading by a set. 

Garbine Muguruza could not keep the momentum going at the Indian Wells Open after winning a WTA title last week and the former world number one was followed out the door by Maria Sakkari.

Muguruza, who claimed the Chicago Fall Tennis Classic, was surprisingly upstaged 6-3 1-6 6-3 by Australia's Ajla Tomljanovic in an upset on Saturday.

Tomljanovic had been 0-6 against top-10 players this year heading into the match but had just enough to edge the fifth seed and two-time grand slam champion with some timely breaks of serve. 

The world number 47 Tomljanovic is into the third round at Indian Wells for the first time in seven appearances and next faces 26th seed Tamara Zidansek. 

"I was really looking forward to playing Garbine, because I did lose [to her] the last couple of times," Tomljanovic said in her on-court interview. "I did try to focus on that one time I beat her [in 2014], and tried to channel that energy, so I was really happy that I got through today."

GOLUBIC STUNS SAKKARI

Sixth seed Sakkari – a semi-finalist at this year's French and US Opens – also fell victim to a shock result, going out 5-7 6-3 6-2 to Viktorija Golubic in their first meeting. 

The pair kept trading service breaks in the opening set, five in all, before Golubic tightened up her game for the final two sets. 

After breaking the Swiss three times in the first set, Sakkari converted just one of four break points the rest of the match. 

Golubic had lost in the first round in her previous two trips to Indian Wells but is now on to the third, where she will face Anna Kalinskaya.

ANDREESCU HOLDS OFF RISKE

Former US Open champion Bianca Andreescu saw a potential straight-sets win slip away before recovering to defeat Alison Riske 7-6 (7-2) 5-7 6-2.

Andreescu – the defending champion after the 2020 WTA Premier 1000 event was cancelled due to the coronavirus pandemic – led 4-1 in the second set but watched her advantage evaporate as Riske forced a decider, which the Canadian ended up taking comfortably as she faced only one break point in the last. 

Top seed Karolina Pliskova eased past Magdalena Frech 7-5 6-2, while third-seeded Barbora Krejcikova was pushed to a third set before prevailing 6-4 3-6 6-1 against Zarina Diyas. 

Angelique Kerber – the 10th seed and three-time major winner – went the distance to beat Katerina Siniakova 6-1 6-7 (4-7) 7-5, while 15th seed Coco Gauff downed Caroline Garcia 6-3 6-7 (2-7) 6-1 in her debut match at the tournament. 

Ons Jabeur, the 12th seed, prevailed 6-2 6-7 (5-7) 6-3 over Anastasija Sevastova and 18th seed Anett Kontaveit – Andreescu's next opponent – moved on when Martina Trevisan retired down 6-3 5-2.