Maria Sakkari defeated Jessica Pegula 7-6 (8-6) 7-6 (7-4) in the opening match of the WTA Finals on Monday in Fort Worth.

It was a highly anticipated first match after the same two competitors faced off in the Guadalajara Open final just eight days ago, with Pegula taking that contest 6-2 6-3 in convincing fashion.

That final lasted just 71 minutes, but the rematch would be a far more gruelling affair, with the first set alone reaching 73 minutes.

Illustrating the even nature of the contest, both players won exactly 52 out of 104 total points played in the opening set, with both players converting three of their five break point opportunities.

Sakkari created a slight edge in the second set, winning 52 per cent of the points (42-of-81) and creating four break point opportunities to Pegula's one.

Pegula took her only chance to break, and then saved two match points to force a tiebreak, but Sakkari would not be denied as she secured the victory and moved to the top of the Group B standings.

BREAK POINTS WON

Sakkari - 4/9

Pegula - 4/6

ACES/DOUBLE FAULTS

Sakkari - 3/1

Pegula - 3/4

WINNERS/UNFORCED ERRORS

Sakkari - 22/22

Pegula - 22/28

There will be one racing certainty when the WTA Finals gets under way: a new champion will be crowned.

Iga Swiatek heads the list of contenders to carry off the trophy in Fort Worth, Texas, having enjoyed a spectacular season.

Ascendant Americans Jessica Pegula and Coco Gauff will be chasing a home victory, while Tunisia's Ons Jabeur has reached finals at Wimbledon and the US Open so loves the big occasion.

Ahead of the tournament getting under way on Monday, Stats Perform has taken a look at the eight-player field.

Swiatek still the player to beat

With no past winner in the line-up, there is every reason to look to the world number one, Swiatek, as favourite.

The 21-year-old Polish player has eight titles this year, lifting trophies at Doha, Indian Wells, Miami, Stuttgart, Rome, the French Open, the US Open and San Diego.

Indeed, she is the only grand slam singles winner in the draw, with Ash Barty having retired and Elena Rybakina absent after no ranking or race points were awarded at Wimbledon, where she was a surprise champion.

Rybakina's absence calls into question the meritocracy of this year's tournament, which is intended to showcase the top performers on tour, yet there can be no doubt the season's premier performer is in the draw.

French Open and US Open winner Swiatek's remarkable run of 10 straight-sets victories in finals (dating back to the 2020 French Open) was finally ended by Barbora Krejcikova, who sprang a shock by winning in Ostrava in early October.

But by getting back to winning ways a week later in San Diego, scrapping for a three-set victory over Donna Vekic in the title match, Swiatek produced a typically impressive response, beating Qinwen Zheng, Gauff and Pegula on her way through the draw to improve to 64-8 in her win-loss record for the year.

Here is a measure of her dominance this season: Swiatek headed the 'Race to the WTA Finals' rankings with 10,335 points, with the players in second (Jabeur) to eighth place (Daria Kasatkina) having tallies ranging between 4,555 and 2,935 points.

Is Pegula the chief rival to Swiatek?

She might not have been the player that would have sprung to mind even a month ago, but Pegula's victory at the Guadalajara Open this month was an eye-opener.

Beginning by saving match points in a thrilling three-setter against Rybakina, Pegula took down grand slam winners Bianca Andreescu, Sloane Stephens and Victoria Azarenka before swatting aside Maria Sakkari in the final.

Pegula has reached quarter-finals at the Australian, French and US Opens in 2022, and she has a tour-high 39 wins in WTA 1000 events since the beginning of last year.

She is up to third in the WTA rankings, one ahead of Coco Gauff, with the United States now having two women in the top five for the first time since October 2010, when Serena Williams was number two and sister Venus sat fourth.

As Pegula said after the Guadalajara final: "I'm definitely a very ambitious person. A little bit of a perfectionist, as well. I don't think you could win if you weren't ambitious, especially at this level.

"I feel like it's going to give me more motivation going forward knowing I can win these big titles. I think it will give me a lot of confidence ending the year, going into next year."

These are spirited words. She heads into the tournament with a 0-4 record against Swiatek in 2022, however.

Who's in, who's out, what's it all about?

As well as Swiatek and Pegula, the field for the eight-day tournament includes Caroline Garcia, Aryna Sabalenka and Sakkari, who have all featured at the WTA Finals in the past.

Four players make their debuts, including Pegula, who is joined as a newcomer by Jabeur, Gauff and Daria Kasatkina.

Gauff, 18, has become the 14th player aged under 19 to reach the WTA top five since the rankings were introduced in 1975.

She would not be the youngest WTA Finals champion, were she to lift the title, as Monica Seles has a tight grip on that record, having triumphed at the age of 16 years and 11 months at the 1990 edition.

Last year's champion Garbine Muguruza is absent. The Spaniard was expected by many to push on and enjoy a stellar 2022 season, but it did not play out that way, with the former French Open and Wimbledon winner sliding to 57th in the world rankings after a dismal campaign.

It goes to show that whoever prevails in Fort Worth, we should be cautious about treating the outcome as an indication of what to expect in the new year.

World number five Jessica Pegula clinched a berth in her second WTA final of the year with a straight-sets victory over Victoria Azarenka at the Guadalajara Open on a rainy Saturday.

Pegula defeated the former world number one Belarussian 7-6 (7-3) 6-1 in one hour and 29 minutes, having fought back from a 4-1 first-set deficit.

The American will need to wait until Sunday to learn her opponent, with rain forcing Maria Sakkari and Marie Bouzkova's semi-final to be suspended and eventually postponed with the Greek leading 7-5.

Pegula's triumph was her 40th win of the season, becoming the 10th American woman to achieve that feat.

The victory also made it four successive Grand Slam winners that Pegula has overcome to reach the final in Guadalajara, knocking off Sloane Stephens, Bianca Andreescu and Elena Rybakina along with Azarenka.

Pegula converted three of eight break points, while Azarenka took her only break point of the match to help her open up the 4-1 first-set lead.

The American proved better on her second serve, while she managed to win 15 of 26 points on Azarenka's second serve.

Sakkari and Bouzkova's semi-final will resume at 1pm local time on Sunday, with the fourth seed leading 7-5 after an epic first set that lasted 84 minutes.

The Greek showed off her grit after fluffing an early 3-1 lead by taking her eighth set point, winning a 22-shot rally - the longest of the first set - to break Bouzkova in the 12th game.

The final is due to commence no earlier than 6pm local time on Sunday, meaning it will be a physical test for the victor.

Maria Sakkari secured the eighth and final place at the WTA Finals after defeating Veronika Kudermetova 6-1 5-7 6-4 to reach the semi-finals at the Guadalajara Open on Friday.

The WTA Finals – which is contested by the women who finish top-eight for the season in ranking points – already had seven entrants locked in, with the eighth to be decided by the winner between world number six Sakkari and world number 12 Kudermetova.

Sakkari's ability to fight her way out of tough situations proved to be the difference as she saved 14 of the 15 break points she faced, while converting three of her nine chances. In the deciding third set, Sakkari made the most of her only break point, while saving all five of Kudermetova's chances to get back into the contest.

She will play Marie Bouzkova in the semi-final after the unseeded Czech was the beneficiary of Anna Kalinskaya's injury retirement in the first set, with Bouzkova leading 5-2.

It continues a terrific run of form for the 24-year-old Bouzkova, who is 19-3 in her past 22 matches, with her only losses in that span coming against world number 20 Karolina Pliskova, Wimbledon champion Elena Rybakina and world number two Ons Jabeur.

On the other side of the draw, Jessica Pegula breezed through the challenge of Sloane Stephens to win 6-2 6-2, which would have set up a tantalising all-American matchup against her doubles partner and rising star Coco Gauff, but she could not hold up her end of the bargain.

Gauff fell 7-6 (7-2) 4-6 6-3 to Victoria Azarenka, giving the Belarusian her third consecutive top-20 win after earning her spot in the quarter-final with victories over world number eight Paula Badosa and world number 15 Madison Keys.

American teenager Coco Gauff showed why she deserves to be at this year's WTA Finals with a commanding 6-0 6-3 victory over Martina Trevisan at the Guadalajara Open.

The fifth seed clinched her maiden spot at the season-ending WTA Finals on Wednesday and backed that up by securing her third WTA 1000 quarter-final on Thursday.

Gauff reeled off the first nine games of the match against Trevisan, where she triumphed in one hour and one minute. The 18-year-old came under pressure from Trevisan, who generated nine break points for the match but Gauff saved all bar one of them.

World number one Iga Swiatek (47) is the only player to have won more matches this year in straight sets than Gauff (32).

Gauff will face Victoria Azarenka in the quarter-finals after the Belarusian toppled 13th seed Madison Keys 6-4 6-7 (4-7) 6-1 in two hours and 13 minutes.

Two-time Australian Open winner Azarenka swept aside Keys in 32 minutes in the third set after a titanic battle in the opening two frames, winning 26 of the 37 final-set points. Azarenka's quarter-final appearance is her 34th since 2009, with only four players having more during the span; Agnieszka Radwanska (42), Simona Halep (39) and Caroline Wozniacki (36).

Third seed Jessica Pegula advanced to the last eight with a 6-4 6-4 victory over former US Open champion Bianca Andreescu. 

The American, who survived three match points against Elena Rybakina on Wednesday, trailed early against the Canadian but took control of the match. Pegula will face Sloane Stephens in the quarter-finals after she toppled 2022 US Open semi-finalist Caroline Garcia 7-6 (8-6) 7-5.

On the day her WTA Finals berth was confirmed, seventh seed Daria Kasatkina lost 6-2 2-6 6-3 to Anna Kalinskaya in two hours and 14 minutes.

Fourth seed Maria Sakkari fought back to win 5-7 6-3 6-3 over 14th seed Danielle Collins, while Marie Bouzkova copped a bagel before triumphing 0-6 7-5 6-3 over Liudmila Samsonova.

Sakkari will next meet eighth seed Veronika Kudermetova who beat Jelena Ostapenko 6-4 6-4. Bouzkova will take on Kalinskaya in the last eight.

The top seed in action on Tuesday at the Guadalajara Open made it through her opening match unscathed as Maria Sakkari defeated Marta Kostyuk 6-4 6-4.

Sakkari is one of the players needing a strong result in the tournament to break into the top-eight of the world rankings to qualify for the upcoming WTA Finals, entering the week at 10th, but only needing to make up one spot, with number eight Simona Halep out due to injury.

With her victory over Kostyuk, Sakkari avoided notching four consecutive losses for the first time this season, and will likely only need one more win to move into WTA Finals contention.

Her next opponent appears to be world number 16 Danielle Collins, who had no issue dispatching American compatriot Caroline Dolehide 6-4 6-1 to book her second-round fixture against Magdalena Frech after the Polish qualifier beat Yulia Putintseva 6-3 6-4.

World number seven Daria Kasatkina also should be locked into the WTA Finals after cruising past China's Lin Zhu 6-1 6-2, while 18th-ranked Beatriz Haddad Maia's season is over after a disappointing 7-5 6-2 upset loss to Katerina Siniakova.

Petra Kvitova needed to reach the final to have a chance of qualifying, but after a strong first set she fell 3-6 6-2 6-0 against Canada's Bianca Andreescu. In a good day for the Canadians, Eugenie Bouchard also beat Kayla Day 7-5 6-3 as the former world number five fights her way back up the rankings after a long injury layoff.

Italy's Elisabetta Cocciaretto defeated Russia's Anastasia Potapova 6-2 6-1, while Latvia's top talent Jelena Ostapenko cruised past America's Lauren Davis 6-1 6-3.

Madison Keys was too strong for Magda Linette in a 6-3 6-3 triumph, and in an all-Czech matchup, Marie Bouzkova downed Tereza Martincova 6-2 7-5.

Croatia's Donna Vekic eliminated Brazil's Laura Pigossi 6-4 6-1, and Italy's Martina Trevisan showed why she is top-30 in the world with a convincing 6-4 6-3 straight sets win against Japan's Nao Hibino.

In the last match of the night, world number 10 Caroline Garcia survived an early scared to come from behind and defeat Rebecca Marino 6-7 (2-7) 6-3 7-6 (7-5).

Donna Vekic produced a spectacular second set to shock world number seven Maria Sakkari 7-6 (7-3) 6-1 in the first round of the San Diego Open on Tuesday.

After a hard-fought first set where both women were able to convert one of their four break point opportunities, Vekic took control in the tie-breaker and carried that momentum in the second set.

Vekic won 65 per cent of her service points in the second set, while Sakkari could only muster a 47-per-cent success rate, despite having a significant edge in first-serve accuracy (79 per cent to Vekic's 53 per cent).

The Croatian only had two break point opportunities, and that is all she needed, taking both to run away with one of the biggest wins of her career.

Vekic will play Karolina Pliskova in the second round after the Czech defeated America's Caroline Dolehide 6-3 6-4.

Pliskova, ranked 22nd in the world, had no issue with the world number 181 in one of Tuesday's biggest mismatches, nabbing a break-to-love in the first set before taking a quick double-break to begin the second.

World number 11 Daria Kasatkina was too strong for Leylah Fernandez, cruising to a 6-2 6-2 victory in exactly one hour.

Sloane Stephens earned a shot against world number five Aryna Sabalenka in the second round after getting the better of Switzerland's Jil Teichmann 6-1 7-6 (7-2).

World number 13 Garbine Muguruza was clearly not at 100 per cent, retiring hurt after losing the first five games of her match against China's Qinweng Zheng, and Coco Gauff will resume her contest against Robin Montgomery leading 6-3 3-2 after rain halted the action for the day.

Anett Kontaveit and Maria Sakkari were both knocked out of the Ostrava Open on Thursday as several top seeds tumbled.

Third seed Kontaveit, who won this competition last year, retired when a set down to Tereza Martincova, while world number seven Maria Sakkari was defeated 5-7 7-5 7-5 by 21-year-old American Alycia Parks in a big upset.

Parks lost the opener but found two crucial breaks of serve when 6-5 up in both the second and third sets to eliminate the fourth seed.

The withdrawal of Belinda Bencica – seeded sixth – with a foot injury put Barbora Krejcikova into the quarter-finals, while Ekaterina Alexandrova will also be in the last eight after overcoming fifth seed Daria Kasatkina 6-1 7-6 (7-1).

The tournament favourites were in much better form at the Jasmin Open in Tunisia, as the top two seeds sealed their places in the quarter-finals with straight-sets wins.

Favourite Ons Jabeur cruised to a 6-1 6-3 victory over Evgeniya Rodina, converting four of her seven break points to safely advance to the next round of her home tournament.

And number two seed Veronika Kudermetova eased past Magdalena Frech 6-3 6-4 to set up a quarter-final meeting with Diane Parry.

Mayar Sherif became the first Egyptian to win a title on the WTA Tour as she toppled Maria Sakkari in Saturday's Parma Ladies Open final.

The 26-year-old from Cairo scored a 7-5 6-3 victory over Greece's world number seven after both won their semi-finals earlier in the day.

Sakkari began the day by beating Danka Kovinic 7-5 6-2, while Sherif earned her place in the title match by battling to a 6-4 3-6 6-4 victory against Ana Bogdan.

The final surprisingly went the way of Sherif, who first entered the WTA top 100 in August of last year and has reached a high of 44th in the rankings.

She began this week at number 74 but will climb again after the biggest success of her career.

"It means a lot for my country," Sherif said. "I'm just thrilled and happy. This was never expected."

Sherif, who studied sports medicine at Pepperdine University in Malibu, California, was understandably weary after her two wins on Saturday. Friday's play had been cancelled due to rain, forcing the players to take to the courts twice on finals day.

"I'm exhausted," Sherif said, quoted on the WTA website. "Today was a very tough day for me, many hours on court. I'm very happy that I pulled it off. I had to dig very deep."

At the Tallinn Open, Sunday's final will be a tantalising tussle between Anett Kontaveit and Barbora Krejcikova.

World number four Kontaveit was a 6-4 6-4 winner against fellow Estonian Kaia Kanepi in their semi-final.

Czech Krejcikova, who won last year's French Open, saw off Swiss second seed Belinda Bencic 6-7 (5-7) 7-6 (7-2) 6-2.

Tallinn Open top seed Anett Kontaveit kept her hopes of winning her home tournament alive with a 6-2 6-1 demolition of Tereza Martincova on Thursday.

The 26-year-old won five out of the final six games as she stormed to the first set, before securing her place in the quarter-finals with a superb second set in which she broke Martincova four times.

Fellow Estonian Kaia Kanepi is also through to the quarter-finals after a 7-5 7-5 victory over Ann Li.

The world number 32 found a crucial break with the opener tied at 5-5 as she took the first set, before breaking Li three times in the second to seal the win.

Eighth seed Shuai Zhang was dumped out by Donna Vekic in a 6-2 6-4 defeat, while fellow seed Jil Teichmann also saw her tournament ended as Ysaline Bonaventure beat her 7-6 (10-8) 6-3.

At the Parma Ladies Open, top seed Maria Sakkari came from a set down for the second consecutive match to overcome Maryna Zanevska and reach the semi-finals.

Zanevska sparked hopes for an upset as she broke the world number seven three times on her way to taking the opening set.

But Sakkari improved in the second to tie the match, before overcoming two breaks of serve from her Belgian opponent to win six of the last seven games and earn a 2-6 6-4 6-4 success.

Sakkari will face Danka Kovinic in the semi-finals, after the 27-year-old's 6-4 6-4 triumph over Italian Jasmine Paolini.

Irina-Camelia Begu's run of 12 consecutive wins on clay came to an end as she was defeated 6-2 7-6 (8-6) by Ana Bogdan in an all-Romanian clash. 

Bogdan's opponent in the final four will be Mayar Sherif, who beat American Lauren Davis 7-6 (7-2) 6-3.

Korea Open finalist Jelena Ostapenko was knocked out in the first round of the Tallinn Open after letting a one-set lead slip against Kaia Kanepi.

Ostapenko looked to be cruising after winning the opener, but Kanepi levelled in the second despite the Estonian watching five set points come and go.

Kanepi then romped to victory with a stunning final set to defeat Ostapenko 4-6 6-4 6-0 and keep her hopes of winning her home tournament alive.

In second-round action, Beatriz Haddad Maia is through to the quarter-finals after a 6-1 7-5 success over Linda Noskova.

After Haddad Maia cruised to a one-set lead, the second was a much tighter affair before the Brazilian's class showed as she broke Noskova and then held serve to earn a straight-sets win.

Second seed Belinda Bencic also secured her place in the final eight with a 6-4 6-7 (2-7) 6-3 triumph over Katie Boulter.

At the Parma Ladies Open, top seed Maria Sakkari came from behind to beat Arantxa Rus and seal her quarter-final spot.

Rus saved five out of five break points as she won the opening set 6-3 to give her hope of an upset.

Those hopes were soon dashed though as world number seven Sakkari broke twice to take the second set 6-2, before clinching the match in the third to tee up a clash with Maryna Zanevska.

World number 33 Irina-Camelia Begu made it 12 consecutive wins on clay by overcoming Matilde Paoletti in straight sets and will face fellow Romanian Ana Bogdan in the next round after she beat Anna Karolina Schmiedlova 6-2 3-6 6-3.

Fourth seed Sloane Stephens saw her tournament come to an end after she was defeated by Danka Kovinic.

Maria Sakkari was made to work as she battled her way back from a set down to reach the last 16 of the Parma Ladies Open.

The number one seed lost the first set to Ukrainian qualifier Kateryna Baindl as a shock appeared to be on the cards.

But the two-time grand slam semi-finalist showed great spirit to eventually win 6-7 (7-2) 6-2 6-3 after two hours and 45 minutes on court.

Fourth seed Sloane Stephens also had to respond to first-set disappointment before coming through 3-6 6-3 6-4 against Magdalena Frech.

The only other seed in action on Monday was Ana Bogdan (sixth), and she had no such issues as she lost just three games in a straightforward win over Brazilian Laura Pigossi that took just 73 minutes.

At the Tallinn Open in Estonia, Belinda Bencic was the highest-ranked player on court on Monday, and the second seed breezed through her first-round clash with local favourite Elena Malygina 6-0 6-2.

Karolina Muchova crushed Jessika Ponchet by the same scoreline, while Barbora Krejcikova, seeded seventh, saw off Ajla Tomljanovic 6-1 7-6 (7-3) in straight sets.

However, there was no joy for Madison Keys; the fourth seed going down 6-3 6-2 against Switzerland's Viktorija Golubic.

Marta Kostyuk defeated Bernarda Pera 6-6 4-6 6-3, and Great Britain's Katie Boulter dropped only four games in her 6-3 6-1 demolition of Jaqueline Cristian, setting up a second-round date with Bencic.

Coco Gauff will reach the highest ranking of her career after the 18-year-old defeated world number six Aryna Sabalenka 7-5 4-6 7-6 (7-4) in the third round of the Canadian Open on Thursday.

Gauff, who has never been ranked higher than her current spot of 11th, will overtake Emma Raducanu and likely Daria Kasatkina to move up to ninth when the next rankings are released after prevailing in an exceptionally tight match against her Belarussian opponent. 

Incredibly, both Gauff and Sabalenka won exactly 131 points each, posting identical success rates on service points (77-of-131) and return points (54-of-131).

Gauff will be considered one of the favourites in the tournament after world number one Iga Swiatek was sensationally eliminated by Brazil's Beatriz Haddad Maia. Swiatek was sloppy, committing nine double faults to just one from her opponent.

Two-time grand slam winner Simona Halep defeated rising Swiss talent Jil Teichmann 6-2 7-5, utilising her dominant first serve to get the job done. Halep converted 82 per cent (32-of-39) of her accurate first serves into points, compared to just 59 per cent (29-of-49) for Teichmann.

World number seven Jessica Pegula had to save a match point on her way to a comeback 3-6 6-0 7-5 win against reigning Canadian Open champion Camila Giorgi, booking her quarter-final clash against Yulia Putintseva after the Kazakhstani beat Alison Riske 6-3 7-5.

Third seed Maria Sakkari went down 1-6 7-6 (11-9) 3-6 against 14th seed Karolina Pliskova, and the Czech will take on China's Qinweng Zheng after she eliminated Canada's last remaining contender Bianca Andreescu 7-5 5-7 6-2.

In the final match of the night, Tokyo Olympics gold medalist Belinda Bencic was incredibly impressive against world number eight Garbine Muguruza, prevailing 6-1 6-3.

The Serena Williams' farewell tour in Toronto is over after she was knocked out of the Canadian Open 6-2 6-4 by 12th seed Belinda Bencic on Wednesday.

Williams, playing for the first time since declaring on Tuesday her intention to retire after this month's US Open, was no match for Tokyo Olympics gold medalist Bencic.

The 23-time major winner was unable to claim back-to-back WTA singles wins for the first time since last year's French Open, having defeated Nuria Parrizas-Diaz for her first victory in 430 days on Monday.

Bencic triumphed in one hour and 17 minutes, winning 84.2 per cent of first-serve points and converted five of eight break points throughout the match.

Williams' power was on show with 13 winners, but Bencic was physically more capable and decisively managed 25 winners with only 13 unforced errors.

Elsewhere, 2019 US Open winner and local hope Bianca Andreescu edged Alize Cornet in a see-sawing clash in the evening, winning 6-3 4-6 6-3 in two hours and 26 minutes.

Fourth seed Paula Badosa and fifth seed Ons Jabeur, who was last month's Wimbledon runner-up, were forced to retire due to injury.

Spanish 24-year-old Badosa withdrew against Yulia Putintseva 7-5 1-0 due to muscle cramping, while Zheng Qinwen had a walkover against Jabeur 6-1 2-1 due to abdominal pain.

Top seed Iga Swiatek brushed aside Ajla Tomljanovic 6-1 6-2 in 64 minutes. The win means Swiatek is the first player to win 15 WTA 1000 matches in straight sets in a row since 2009.

Canadian 13th seed Leylah Fernandez also bowed out, going down 7-6 (7-4) 6-1 to Brazil's Beatriz Haddad Maia, who will face Swiatek in the third round.

Second seed Anett Kontaveit lost 6-4 6-4 to Jil Teichmann in one hour and 27 minutes. Teichmann will next face Simona Halep who won in 71 minutes against Zhang Shuai 6-4 6-2.

Sixth seed Aryna Sabalenka got past Sara Sorribes Tormo 6-4 6-3 to set up a third-round meeting with Coco Gauff after she defeated Wimbledon champion Elena Rybakina 6-4 6-7 (8-10) 7-6 (7-3) in an epic that lasted two hours and 49 minutes.

Jessica Pegula won 6-2 7-5 over American qualifier Asia Muhammad to progress through to face Camila Giorgi after she knocked off Elise Mertens 7-3 7-5.

Third seed Maria Sakkari triumphed in three sets 6-2 4-6 6-2 over Sloane Stephens and will face Karolina Pliskova next after the Czech beat Amanda Anisimova 6-1 6-1.

Eighth seed Garbine Muguruza won 6-4 6-4 against Kaia Kanepi and Alison Riske toppled 16th seed Jelena Ostapenko 7-6 (7-2) 0-6 7-5.