The Women's Tennis Association (WTA) has opened an investigation into Peng Shuai's sexual assault allegations against a former China leader.

Shuai, 35, posted on Chinese social media site Weibo allegations against Zhang Gaoli – the ex-vice premier and member of the Chinese Communist Party's Politburo Standing Committee – claiming he had forced her to have sexual relations with him.

In the post, published on Tuesday before subsequently being deleted, the 2013 Wimbledon doubles champion alleged that the pair had extramarital relations and she had developed feelings for him.

All of Peng's content has since been removed from Weibo and numerous reports suggest she has not been seen in recent days.

The WTA's chairman Steve Simon addressed the matter on Sunday in a statement that said: "The recent events in China concerning a WTA player, Peng Shuai, are of deep concern. As an organisation dedicated to women, we remain committed to the principles we were founded on – equality, opportunity and respect.

"Peng Shuai, and all women, deserve to be heard, not censored. Her accusation about the conduct of a former Chinese leader involving a sexual assault must be treated with the utmost seriousness.

"In all societies, the behaviour she alleges that took place needs to be investigated, not condoned or ignored. We commend Peng Shuai for her remarkable courage and strength in coming forward.

"Women around the world are finding their voices so injustices can be corrected.

"We expect this issue to be handled properly, meaning the allegations must be investigated fully, fairly, transparently and without censorship.

"Our absolute and unwavering priority is the health and safety of our players. We are speaking out so justice can be done."

Top seed Aryna Sabalenka bounced back from a disappointing defeat in her opening match at the WTA Finals to rally past Iga Swiatek in Guadalajara. 

Sabalenka steadied herself after dropping the opening set and prevailed 2-6 6-2 7-5 Saturday to keep alive her hopes of reaching the semi-finals in her maiden appearance at the event. 

Swiatek, the youngest player in the field at age 20, broke Sabalenka in her final two service games of the first set but could not maintain the momentum as the Belarusian returned the favour in the second. 

Sabalenka entered Saturday with a 9-13 record in three-set matches compared to 35-4 in two-setters but maintained her nerve after the pair traded breaks early in the decider. 

The world number two broke Swiatek to take a 6-5 lead, then served the final game out at love for the victory. 

With Sabalenka's win, Paula Badosa advances to the semi-finals as winner of the group, while the winner of Monday's match between Sabalenka and Maria Sakkari also will advance. Swiatek is out of contention for the semis. 

History is not necessarily on Sabalenka's side, as the top seed has failed to advance from the group stage at three of the past five WTA Finals. 

WINNERS/UNFORCED ERRORS 

Sabalenka – 16/27
Swiatek – 15/18

ACES/DOUBLE FAULTS 

Sabalenka – 8/16
Swiatek – 2/3

BREAK POINTS WON 

Sabalenka – 4/7
Swiatek – 3/7

Paula Badosa made it two wins from two at the WTA Finals as she saw off a battling Maria Sakkari in straight sets.

In-form Badosa triumphed 7-6 (7-4) 6-4 in two hours and four minutes to win her eighth straight match, having come into the tournament on the back of her triumph at Indian Wells.

Permutations for the last round of group-stage matches in Guadalajara will become clearer after Aryna Sabalenka has taken on Iga Swiatek later on Saturday.

But after beating Sabalenka and Sakkari without dropping a set, Badosa looks all but certain to reach the semi-finals on her debut appearance at the event.

In the first meeting between the two players, Badosa led 5-2 only to be forced into an opening-set tie-break by Sakkari, who then undid her hard work by losing the first four points of the breaker, with the Spaniard ultimately sealing the first set courtesy of a fine forehand.

Badosa struck first again with a break early in the second set and although Sakkari was able to level matters at 4-4, her opponent broke decisively immediately after before serving it out, converting her third match point with a backhand winner.

WINNERS/UNFORCED ERRORS 

Sakkari – 25/49
Badosa – 23/22

ACES/DOUBLE FAULTS 

Sakkari – 1/4
Badosa – 10/6

BREAK POINTS WON 

Sakkari – 2/5
Badosa – 3/12

Anett Kontaveit stormed into the last four of the WTA Finals by securing a hugely impressive 6-4 6-0 victory over Karolina Pliskova on Friday. 

Estonian eighth seed Kontaveit overcame Barbora Krejcikova in her opening match and became the first player to reach the semi-finals in Guadalajara by racking up a career-best 12th straight win in just 57 minutes. 

Pliskova was victorious in each of the pair's previous three meetings and applied some early pressure but was unable to convert any of the three break points she engineered in game three of the opening set. 

Kontaveit, meanwhile, pounced on her first opening, showing the clinical touch that has seen her pick up recent titles in Moscow and Cluj-Napoca with a winner to take the set. 

The world number eight reeled off the next six games to guarantee a top-two finish in Group Teotihuacan and secure a tour-leading 38th hard-court match win this year. 

Pliskova could yet salvage a place in the semi-finals by overcoming Barbora Krejcikova in her final round-robin match, though.

WINNERS/UNFORCED ERRORS 

Kontaveit – 20/16 
Pliskova – 9/18 

ACES/DOUBLE FAULTS 

Kontaveit – 6/3 
Pliskova – 4/2 

BREAK POINTS WON 

Kontaveit – 4/6 
Pliskova – 0/3 

Maria Sakkari was merciless as she began her WTA Finals campaign with a comfortable 6-2 6-4 win over an Iga Swiatek who became visibly emotional towards the end.

It was Sakkari's eighth win over a top-10 opponent this season, the most of any player on the WTA Tour, while the victory took her to 3-0 against Swiatek this year.

Sakkari, with her trademark intensity and feistiness, appeared to adjust to the conditions and altitude of Guadalajara much better than her opponent, who looked lethargic during the first set.

This was particularly evident in the 20-year-old's second service game, as Sakkari converted the second of her break points to get the early advantage.

Swiatek showed the occasional flash of quality, such as an awesome out-of-the-blue cross-court forehand in the fifth game, but she soon found herself 5-2 down as Sakkari broke to love, the decisive point gifted to her by a sloppy volley at the net that the Pole inexplicably put beyond the sideline.

Sakkari quickly wrapped up the set but Swiatek was able to dig a bit deeper in the second, showing great determination to eventually hold serve during the 10-minute third game.

But her body language at the change was hardly indicative of a player convinced she could level the match, as she sat there with a towel draped over her from head to knees.

Swiatek held out for another few games but Sakkari got the decisive break to go 4-3 up, and the match ultimately went with serve from there.

Sakkari finished her opponent off by serving to love, with a tearful Swiatek given a code violation for turning her back as she attempted to regain her composure before facing triple match point, ultimately putting her return into the net.

WINNERS/UNFORCED ERRORS

Sakkari – 15/22
Swiatek – 8/29

ACES/DOUBLE FAULTS

Sakkari – 2/5
Swiatek – 2/6

BREAK POINTS WON

Sakkari – 3/8
Swiatek – 0/2

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.

Emma Raducanu vowed to maintain her focus in the wake of her sensational US Open title as she prepares for her first WTA Tour event as a number one seed. 

Ranked a career-best number 21 in the world, the 18-year-old sensation is atop the singles draw at the Upper Austria Ladies Linz this week. 

Raducanu's remarkable run at Flushing Meadows has generated an avalanche of publicity and requests, but she insisted tennis will remain her top priority. 

"I made it very, very clear to every single person in my team that I was not going to cancel one training session or practice session for any off-court commitments," Raducanu told reporters. 

"That was non-negotiable for me. I wanted to make sure that that is my priority and it is, so everyone is clear about that. But it's just managing my time with the commitments around that."

Raducanu has a bye in the first round and will face the winner of the opening-round match between qualifiers Kateryna Kozlova and Wang Xinyu. 

The teen split with coach Andrew Richardson after the US Open and remains without an official adviser but said she plans to have someone in place by January's Australian Open. 

That was not something she would have anticipated worrying about during last year's tournament in Melbourne, when she was still a full-time student. 

"Only March the 18th was my first session on court in 2021," she said. "And so January, February, March I was literally just sat on my desk staring at a wall for nine hours a day.

"So I feel like where I am now I just need to really take it all in and enjoy because looking back at how far I've come it's pretty surreal.

"I just really need to enjoy it because when I was in the beginning of year I would have never thought this was possible. I'm kind of just really living in the moment right now I feel."

Late stand-in Liudmila Samsonova produced a mesmerising fightback to beat Olympic champion Belinda Bencic and clinch the Billie Jean King Cup for the Russian Tennis Federation.

After Daria Kasatkina swept to a 6-2 6-4 win over Jil Teichmann to put the Russians ahead against Switzerland, Samsonova produced a high-quality performance to win 3-6 6-3 6-4 against Bencic.

It meant there was no need for a doubles decider, with the Russian squad taking the match 2-0.

Samsonova had not expected to be involved in the singles contest in Prague, but a knee problem forced Anastasia Pavlyuchenkova to pull out just minutes before Saturday's final got under way, forcing Russian captain Igor Andreev into a reshuffle.

A worthy substitute, Samsonova is ranked 40th in the world, while Bencic sits at number 17, and this win was the Russian's third victory in three meetings this year with the Tokyo 2020 gold medallist.

One of those came in the final of the Berlin grass-court tournament, and the 22-year-old was not over-awed by another big occasion this time.

Just as she did in Berlin, Samsonova lost the opening set but then dominated, and by doing so she secured a fifth Russian triumph in this team competition, previously known as the Fed Cup.

Samsonova said: "I have too many emotions now. It's unbelievable. I'm unbelievably happy. It was an incredible fight. It was a more nervous game. It was more than tennis."

Andreev spoke of the strong bond in his squad, saying: "It's an historical win for us. It's been a long time without any trophies in team tennis. I'm very proud and very happy for the girls, the way they played.

"They're amazing, they're heroes, and they achieved this because they're a team – a real team – and real friends."

Russia dominated this event from 2004 to 2008, winning four of five titles, while Switzerland had only previously been to one final, when Martina Hingis and Patty Schynder were outmatched by Arantxa Sanchez Vicario and Conchita Martinez in the 1998 showpiece.

Serena Williams says the hamstring injury that forced her out of Wimbledon in the first round is "better" and she plans to play at the 2022 Australian Open. 

The site of her last grand slam crown in 2017 will be Williams' next chance to equal Margaret Court's record of 24 career slam titles. 

The 40-year-old tore her hamstring while playing Aliaksandra Sasnovich at SW19 in June and recounted the injury in an appearance Thursday on Jimmy Kimmel Live. 

"I was actually winning and I went for a shot and I heard this noise and I was like ‘oh no’," Williams said. "I felt it but I felt like 'OK, let me just keep trying', but it was bad and I was like, ‘oh man’.

"I love the grass, it’s something special walking out at Wimbledon, wearing all white and being on the green grass [but] it just wasn’t for me this year.”

The injury kept Williams out of the US Open, where she has not won since 2014 but reached the semi-finals in 2020 and the final in 2018 and 2019. 

While disappointed to miss her home slam, which she has won six times, Williams told Kimmel her recovery is on track and she "definitely" expects to play in Australia in January. 

"The hamstring is better," she said. "It took a long time. It took forever, but it's much better now." 

Williams is a seven-time champion in Melbourne, the most of any woman in the open era. 

Veronika Kudermetova and Liudmila Samsonova propelled a Russian tennis squad into their first Billie Jean King Cup final since 2015 as they sealed a 2-1 victory over the United States.

The Russians will meet Switzerland in the trophy showdown on Saturday, after Olympic champion Belinda Bencic defeated Ajla Tomljanovic to secure an unassailable 2-0 lead for the Swiss over Australia.

While Switzerland did not need a doubles decider, the Russian team, who are competing this week as Russian Tennis Federation, did.

Samsonova, who clinched her maiden singles title on the WTA Tour earlier this year, put them ahead in their tie against the USA, downing 2017 US Open champion Sloane Stephens 1-6 6-4 6-3.

Yet the USA hit back through Danielle Collins, who defeated Anastasia Pavlyuchenkova 6-7 (9-11) 7-6 (7-2) 6-2 – a contest that lasted two hours and 42 minutes in Prague.

Momentum was with the 18-time champions, but the Russians recovered in the doubles, with Samsonova and Kudermetova ultimately having little trouble in seeing off Shelby Rogers and Coco Vandeweghe 6-3 6-3.

Bencic saw off Tomljanovic to confirm Switzerland's place in the final, with Jil Teichmann having earlier overcome Storm Sanders 6-0 6-3.

Russia dominated this event, previously known as the Fed Cup, in the mid to late 2000s, winning four out of five editions from 2004 to 2008, but they have not triumphed since. Switzerland recorded their best result when a team featuring Martina Hingis finished second to Spain, way back in 1998.

Australia and Switzerland secured their spots in the semi-finals of the Billie Jean King Cup and will go up against each other for a place in the final.

Belarus proved no match for Australia, who got the job done across their two singles matches on the day in the Czech Republic.

Storm Sanders got the ball rolling as she comfortably saw off Yuliya Hatouka 6-3 6-3 in the first contest of the day in Group B.

Ajla Tomljanovic was made to work a little harder by Aliaksandra Sasnovich as she lost the first set but eventually rallied to overcome her opponent 4-6 6-2 6-3.

It meant the two countries' doubles meeting was a dead rubber – Belarus at least took the opportunity to avoid a 3-0 annihilation as Sasnovich teamed up with Lidziya Marozava in the 6-4 6-4 defeat of Olivia Gadecki and Ellen Perez.

In Group D, Switzerland and the Czech Republic claimed one victory apiece in the singles – Marketa Vondrousova had too much for Viktorija Golubic in a 6-4 6-2 success that gave the Czechs the upper hand.

But Belinda Bencic levelled things up despite the unenviable task of facing world number three Barbora Krejcikova, emerging with a 7-6 (7-2) 6-4 success.

Bencic was then involved in the doubles decider as well, getting the better of Lucie Hradecka and Katerina Siniakova with Jil Belen Teichmann, their 6-3 6-3 win sealing the semis spot for the Swiss.

The Russian Tennis Federation – who eliminated defending champions France on Wednesday – and the United States are due to contest the other semi-final.

France's Billie Jean King Cup defence ended at the hands of the Russian Tennis Federation, who will meet the United States in the semi-finals after Wednesday's play in Prague. 

Clara Burel put France on course for the 3-0 victory they needed to advance from Group A with a three-set victory over Ekaterina Alexandrova, but Anastasia Pavlyuchenkova outlasted Alize Cornet in the second rubber to ensure a new champion will be crowned. 

Pavlyuchenkova saved six of 10 break points and racked up an impressive 34 winners en route to a crucial 5-7 6-4 6-2 success against Cornet. 

"I'm so, so happy and so proud of myself because I think it was an incredible match. It was very good tennis but more importantly I think it was an amazing fighting spirit from both of us," said Pavlyuchenkova. 

"We were like two tigers. Nobody wanted to give the other anything and I think that's what matters. That's the sport we're playing." 

Veronika Kudermetova and Liudmila Samsonova comfortably defeated Cornet and Burel in the doubles to consign the reigning champions to a 2-1 defeat. 

The RTF will go up against the USA in the first semi-final, with the Americans comfortably seeing off Spain in the singles rubbers. 

Sloane Stephens bested Nuria Parrizas-Diaz 6-4 6-4 before Danielle Collins swept Sara Sorribes Tormo aside 6-1 6-0 in under an hour. 

Collins won 83 per cent of points behind her first serve and forced Sorribes Tormo into 24 errors during a resounding victory. 

Spain avoided a 3-0 defeat, though, with Aliona Bolsova and Rebeka Masarova beating Caroline Dolehide and CoCo Vandeweghe 6-3 6-4 in the doubles rubber. 

Belinda Bencic fought back to beat Angelique Kerber in a blockbuster showdown and help Switzerland eliminate Germany on day two of the Billie Jean King Cup in Prague.

Germany lost to hosts Czech Republic on the opening day and were brushed aside 3-0 by Switzerland on Tuesday, with world number nine Kerber losing 5-7 6-2 6-2 to Bencic.

Kerber was carrying an injury and was outlasted by the Olympic gold medallist, with that triumph coming after Viktorija Golubic defeated Andrea Petkovic 6-4 7-5.

Golubic and Jil Teichmann added further gloss to the scoreline by overcoming Anna-Lena Friedsam and Nastasja Mariana Schunk in the doubles.

Switzerland will now meet the Czech Republic in a winners-takes-all contest to determine who finishes top of Group D.

The upset of the day came in Group B as Australia beat Belgium 2-1, with Daria Gavrilova kicking things off by beating Greet Minnen 6-4 1-6 6-4.

Storm Sanders then battled back to beat Elise Mertens 4-6 7-6 (7-5) 6-0, rendering Mertens and Minnen's doubles win nothing more than a consolation. 

In Group A, Russia cruised to a 3-0 win over Canada.

Daria Kasatkina beat Carol Zhao 6-3 6-1 and Anastasia Pavlyuchenkova was too strong for Rebecca Marino as she prevailed in three sets.

Slovakia top Group C, meanwhile, after beating the United States 2-1. Shelby Rogers fell 6-4 6-4 to Viktoria Kuzmova before Danielle Collins levelled with a 6-3 6-2 win against Anna Karolina Schmiedlova.

That set up a decider in the doubles, which went the distance as the Slovakian pair of Kuzmova and Tereza Mihalikova prevailed 6-2 6-7 (5-7) 12-10 in a thriller with Caroline Dolehide and CoCo Vandeweghe.