Garbine Muguruza continued her superb start to 2021 as the former world number one won a WTA Tour-leading 21st match of the season to progress at the Volvo Car Open.

Muguruza – the sixth seed in Charleston – dispatched qualifier Magdalena Frech 6-1 6-3 in her first match of the clay court season on Tuesday.

Two-time grand slam champion Muguruza has already reached three finals this year, winning once in Dubai, and took just 70 minutes to overcome Fech on her return to Charleston following an eight-year absence. 

"I'm happy that I got this win, that I fought hard, that I kept my fighting spirit through the whole match, also in the second set which was tighter than the first set," Muguruza told reporters, in quotes reported on the WTA's official website.

Joining Muguruza in the round of 16 is third seed and fellow former grand slam champion Petra Kvitova, who saw off Storm Sanders 7-6 (7-4) 6-2 in her first-ever match at the WTA Premier tournament. 

Meanwhile, two former Charleston champions will go head-to-head after Sloane Stephens – a winner in 2016 – beat lucky loser Xinyu Wang 6-2 6-4 to tee up a second-round tie with 2019 victor Madison Keys.

Shelby Rogers took advantage of being in familiar surroundings by seeing off Kristina Mladenovic, while Monterrey Open champion Leylah Fernandez also progressed at the expense of 16th seed Shuai Zhang.

As for American sensation Coco Gauff, the 14th seed beat Tsvetana Pironkova 6-3 6-0 en route to the last 32.

There was a first-round surprise at the Colsanitas Cup in Bogota, where second seed Sara Sorribes Tormo was upstaged by 2012 French Open runner-up Sara Errani 7-5 7-5.

Colombian youngster Maria Camila Osorio got the better of American Sachia Vickery 6-3 6-2, with a potential top-100 scalp of Tereza Martincova next in her sights.

Amanda Anisimova, Alize Cornet and Paula Badosa all survived scares on Monday to advance through to the second round of the Volvo Car Open in Charleston.

Number 13 seed Anisimova came from a set down to beat Magda Linette 5-7 6-2 6-3 on Monday, dropping serve only once in those last two sets.

Cornet, who reached the quarter-finals of this event in 2018, needed just under three hours to overcome Bernarda Pera 4-6 6-4 6-4.

Badosa also needed all three sets to see off Varvara Gracheva, the Spaniard hitting back to prevail 3-6 7-5 6-1.

Ajla Tomljanovic and Zarina Diyas were also among those to book a place in the next round, beating Christina McHale and Natalia Vikhlyantseva respectively in straight sets.

In the other WTA Tour event, Copa Colsanitas top seed Zheng Saisai eased past Usue Maitane Arconada 6-3 6-1 and will now face Stefanie Voegele.

Wang Yafan was another Chinese player to advance in Bogota, seeing off Emiliana Arango 6-4 5-7 7-5.

Next month's French Open could be postponed amid the ongoing coronavirus pandemic, according to France's minister of sports.

France entered its third national lockdown on Saturday in a bid to halt another surge of COVID-19 cases, which had threatened to overwhelm hospitals across the country. 

Professional sporting events are largely exempt from the restrictions, but minister of sports Roxana Maracineanu has suggested the French Open could be put back from its scheduled May 23 start date.

"We are in discussions with them [the French Tennis Federation] to see if we should change the date to coincide with a possible resumption of all sports and major events," she told radio station France Info.

"Today, although high-level sport has been preserved, we try to limit the risks of clusters, of spreading the virus within professional sports."

Rafael Nadal won last year's French Open, which was postponed by four months, to pull level with Roger Federer's record of 20 grand slam titles.

Maria Sakkari insisted there was still room for improvement despite ending Naomi Osaka's 23-match winning streak in stunning fashion at the Miami Open.

Osaka had not lost for over a year prior to Wednesday's outing, putting together the ninth-longest unbeaten run seen on the WTA Tour since the start of 2000.

However, this year's Australian Open champion was simply unable to match her opponent's high standards in their quarter-final clash, resulting in a 6-0 6-4 triumph for the excellent Sakkari.

World number 25 Sakkari had battled hard to get past Jessica Pegula in the previous round – including saving six match points – but needed just 69 minutes to see off four-time grand slam champion Osaka, who managed just five winners during her surprisingly brief stint out on court.

Afterwards, Sakkari revealed how coach Tom Hill helped devise a strategy to trouble the second seed – albeit she had to come from 3-0 down after a difficult start to the second set.

"I don't think tennis-wise it was like the best tennis I have ever played in my life," said Sakkari, according to the WTA Tour's website.

"I think I executed our strategy with Tom really well. I just did what I had to do. I'm not gonna tell you what. What we discussed before the match, I just did it most of the match, except maybe a couple of games where things didn't go right."

Osaka's previous loss was back in February 2020, when she was also beaten in straight sets by Sara Sorribes Tormo at the Billie Jean King Cup.

Since then, she has won last year's US Open and then the first grand slam in 2021, though the loss to Sakkari did not come as a complete surprise to her having struggled for rhythm in Miami.

"She's a really big fighter so I knew it wasn't going to be easy. I felt like I haven't been playing well this whole tournament," Osaka said.

"I couldn't find a groove, so mentally it's really hard for me to play against really high-quality players with what I feel is low-quality tennis."

Next up for Sakkari in the semi-finals is another former grand slam champion – Bianca Andreescu.

Triumphant at Flushing Meadows in 2019, eighth seed Andreescu outlasted Sorribes Tormo 6-4 3-6 6-3 in the day's final match at the WTA Premier event.

Ash Barty's grip on the world number one ranking remains for now after winning in three sets against seventh seed Aryna Sabalenka in the Miami Open quarter-finals on Tuesday.

The 2019 Miami Open champion defeated Sabalenka 6-4 6-7 (5-7) 6-3 in humid conditions in South Florida to reach the last four, where the Australian will face fifth seed Elina Svitolina.

Svitolina won in the later match on Tuesday over Latvia's Anastasija Sevastova 6-3 6-2.

Barty, the 2019 French Open champion, did not drop her serve once against the Belarusian, saving seven break points throughout the match as she bids to retain her top ranking.

Barty is under threat from 2021 Australian Open winner Naomi Osaka for the number one ranking, with the Japanese also into the quarters.

The Australian will retain the top ranking by reaching the decider, regardless of second seed Osaka's results.

"It was a brilliant match today," Barty said in her on-court interview. "It was certainly the best level I’ve played for a long time and especially over a sustained period.

"Aryna really made me bring out my best stuff today. She’s an exceptional competitor."

Barty has now won 10 consecutive matches in Miami, dating back to her 2019 title with 2020's event cancelled due to the COVID-19 pandemic.

Ukraine's Svitolina, ranked fifth in the world, reached the Miami Open semi-finals for the first time with her win over the unseeded Sevastova.

"I've always wanted to play well here in Miami," said Svitolina, who made last year's French Open quarter-finals.

"It's one of the biggest tournaments and playing here is always amazing, so I'm really pleased with the performance tonight."

World number two Naomi Osaka and defending champion Ash Barty advanced to the quarter-finals of the Miami Open.

Osaka reached the last eight at the WTA Premier event for the first time in her career thanks to Monday's straight-sets win over Elise Mertens.

World number one Barty overcame two-time grand slam champion Victoria Azarenka in a tough three-set battle in Miami.

THERE'S NO STOPPING OSAKA

Australian Open champion Osaka extended her winning streak to a remarkable 23 matches.

Osaka defeated 16th seed Mertens 6-3 6-3 to stay hot – Venus Williams, Serena Williams, Justine Henin and Azarenka are the only other players with winning streaks of 23 or more matches since 2000.

"It definitely feels very special," four-time major winner Osaka said. "This is one of my favourite tournaments to play, and of course I'm sad I hadn't been able to get to the second week the last times that I have played this tournament. But I'm here now, and hopefully it will go well this time."

Maria Sakkari is next for Osaka after the 23rd seed saved six match points in her 6-4 2-6 7-6 (8-6) win over Jessica Pegula.

BARTY WINS BATTLE OF PAST AND PRESENT NUMBER ONES

In a rollercoaster battle, top seed Barty prevailed 6-1 1-6 6-2 against 14th seed Azarenka.

Barty extended her winning streak in Miami to nine matches after coming out on top against the former world number one.

"Playing against Vika you have to be ready right from the first point," Barty said. "I felt like I did that well in the first set and she gave me a few cheap errors. Then through the second she lifted her intensity.

"I probably wasn't sharp enough in those first couple of games to be able to go with her, particularly with new balls. When Vika is ahead and she's a front runner, she's the very best in the world."

Aryna Sabalenka stands in the way of Barty and the semi-finals after the seventh seed trounced Marketa Vondrousova 6-1 6-2.

SVITOLINA WINS THRILLER, ANDREESCU RALLIES

Fifth seed Elina Svitolina rallied past two-time Wimbledon winner Petra Kvitova 2-6 7-5 7-5.

Svitolina made a slow start against the red-hot ninth seed, but the 2018 WTA Finals champion finished strongly to progress.

Anastasija Sevastova took down Ana Konjuh 6-1 7-5 to set up a clash with Svitolina.

Meanwhile, eighth seed and 2019 US Open champion Bianca Andreescu came from behind to defeat two-time slam winner Garbine Muguruza 3-6 6-3 6-2.

Naomi Osaka did not raise a sweat en route to the Miami Open last 16 as Garbine Muguruza moved through but Sofia Kenin and Karolina Pliskova bowed out.

Australian Open champion and second seed Osaka benefited from a walkover after qualifier Nina Stojanovic withdrew ahead of Sunday's clash due to a right thigh injury.

Elise Mertens will face Osaka following the 16th seed's 6-2 0-6 6-2 win against Anett Kontaveit.

Two-time grand slam winner Muguruza rallied past Russian wildcard Anna Kalinskaya at the WTA Premier event.

However, fourth seed Kenin was sent packing as sixth seed Pliskova was tamed by nemesis Jessica Pegula in Miami.

MUGURUZA STAYS HOT

Spanish star Muguruza dug deep to earn her tour-leading 20th win of the season.

Former world number one Muguruza – the 12th seed – prevailed 4-6 6-3 6-4 against Kalinskaya, having trailed 3-0 in the final set.

"I brought my fighting spirit and I could match the level of fighting against Anna, and very happy to go through these tough matches," Muguruza said following two hours, 41 minutes on court.

"Doesn't matter if you play pretty or you play ugly, but you stay strong and you go through these rounds. That gives me an opportunity to feel better and to have another chance."

Muguruza – who has the most final appearances this season with three, having won the Dubai Tennis Championships and finished runner-up at the Qatar Open and Yarra Valley Classic – will next face eighth seed Bianca Andreescu.

Former US Open champion Andreescu overcame fellow seed Amanda Anisimova 7-6 (7-4) 6-7 (2-7) 6-4.

KENIN'S WOES CONTINUE

It has been a rough 2021 for American star Kenin.

Stunned in the second round of the Australian Open – in her title defence – Kenin then crashed out of the Phillip Island Trophy at the first hurdle.

Kenin rallied to beat Andrea Petkovic first-up in Miami, but the 22-year-old was beaten 6-4 4-6 6-4 by 27th seed Ons Jabeur.

Jabeur and Sara Sorribes Tormo – who shocked 21st seed Elena Rybakina 6-1 3-6 6-2 – will meet for a spot in the quarter-finals.

PLISKOVA FALLS TO PEGULA… AGAIN

For the third time this past month, 2019 Miami Open runner-up Pliskova went down 6-1 4-6 6-4 to 29th seed Pegula.

Australian Open quarter-finalist Pegula conquered Pliskova in Doha and Dubai before repeating the feat in Miami on Sunday.

"I played her a lot the last three weeks, three tournaments," Pegula said. "I kind of expected her to play well there. Even when I was up I still felt like she could easily come back just because she plays so aggressive and she serves well."

After reeling off the final four games, Pegula set up a last-16 showdown with 23rd seed Maria Sakkari, who dismantled qualifier Liudmila Samsonova 6-0 6-1.

World number one Ash Barty moved through to the last 16 of the Miami Open, where Simona Halep's campaign came to a premature end.

Defending champion and top seed Barty was too good for Jelena Ostapenko in Saturday's showdown between the former French Open winners.

Two-time grand slam winner Victoria Azarenka also moved through to the fourth round of the WTA Premier tournament.

Halep, however, succumbed to a shoulder injury in Miami.

CLASH OF PAST AND PRESENT NUMBER ONES

Barty and former world number one Azarenka will go head-to-head for a place in the quarter-finals.

Australian star Barty accounted for Ostapenko 6-3 6-2 as she extended her winning streak at the Miami Open to eight matches.

Barty, who tallied nine winners to 14 unforced errors, rallied from 2-0 down in the second set by reeling off six successive games to advance.

"Today felt like I was a lot sharper and switched on and ready to go from the very first point," Barty said afterwards.

Three-time Miami champion Azarenka trumped Angelique Kerber 7-5 6-2 in the third round.

Azarenka – the 14th seed – fought back from a 4-1 deficit in the opening set to get the better of the three-time major winner.

"She's a very talented player. I always have been a huge fan of her game and the way she plays, the way she handles herself. She has a lot of variety," Azarenka said on facing Barty. "She has pretty much every single shot there is. [It's] going to be a great match."

INJURED HALEP PULLS OUT

Two-time grand slam champion Halep withdrew due to a shoulder injury as Anastasija Sevastova benefited from a walkover.

"I'm very sorry to I have to pull out of the singles and doubles at the Miami Open, but my injury doesn't let me play here as expected," said Halep.

"I'm sad that I can't continue, I wanted to come here to give my best and play many matches but unfortunately I can't. 

"Hopefully next year I will come back healthy and better."

Next up for Sevastova is wildcard Ana Konjuh, who stunned 15th seed and reigning French Open champion Iga Swiatek 6-4 2-6 6-2.

SVITOLINA AND SABALENKA ROLL ON

Ukrainian fifth seed Elina Svitolina booked her spot in the round of 16 after overcoming fellow seed Ekaterina Alexandrova 7-6 (7-1) 6-4.

Two-time Wimbledon winner Petra Kvitova stands in the way of a quarter-final berth – the ninth seed was too good for 17th seed Johanna Konta 6-1 6-2.

Seventh seed Aryna Sabalenka, meanwhile, prevailed 7-6 (7-4) 6-4 against Veronika Kudermetova.

Belinda Bencic – the 11th seed – was sent packing 4-6 6-4 6-4 by Marketa Vondrousova, who will take on Sabalenka.

Simona Halep has withdrawn from the Miami Open due to a shoulder injury.

Halep beat Caroline Garcia in the second round in Florida on Thursday, but an issue with the world number three's right shoulder prevented her from facing Anastasija Sevastova.

The two-time grand slam champion said: "I'm very sorry to I have to pull out of the singles and doubles at the Miami Open, but my injury doesn't let me play here as expected.

"I'm sad that I can't continue, I wanted to come here to give my best and play many matches but unfortunately I can't. 

"Hopefully next year I will come back healthy and better."

Sevastova will face either French Open champion Iga Swiatek or Ana Konjuh in the round of 16.

Second seed Naomi Osaka picked up where she left off at last month's Australian Open, winning her first match since lifting the title in Melbourne.

Osaka earned her place in the Miami Open third round on Friday with a hard-fought straight-sets victory over Australian Ajla Tomljanovic.

Australian Open runner-up Jennifer Brady was knocked out in the second round by 58th-ranked Sara Sorribes Tormo.

Brady's defeat was the major surprise on Friday, with Sorribes Tormo fighting back from a set down to win.

Top 10 seeds Karolina Pliskova, Bianca Andreescu and Sofia Kenin also progressed, with the latter coming from a set behind to beat Andrea Petkovic.

OSAKA CONTINUES WINNING RUN

Osaka extended her winning streak to 22 matches, although it was not easy against Tomljanovic.

The Japanese got the edge 7-6 (7-3) 6-4, firing down 36 winners, including 13 aces in a match lasting one hour, 38 minutes.

"This is my first match since Australia, so I just really wanted to play well," Osaka said in her on-court post-match interview. "I kind of feel like I'm at home here, because I grew up [near here] for most of my life."

Tomljanovic did not go down without a fight but was let down by 24 unforced errors.

Osaka will next face Serbian qualifier Nina Stojanovic in the third round.

BRADY BEATEN AGAIN

World number 14 Brady succumbed to in-form Monterrey Open semi-finalist Sorribes Tormo 3-6 6-4 6-1.

Brady had a dream run to the final at the Australian Open last month but came back to earth with a thud against the Spaniard, who has won 10 of her past 11 matches.

The match lasted two hours, 22 minutes, with Sorribes Tormo finding the edge in the last as Brady's first-serve percentage dropped to 30.8 per cent.

Brady's defeat comes a few weeks after being humbled by Anett Kontaveit in less than an hour in the Qatar Open first round.

MIXED BAG FOR SEEDS

Tenth seed Kiki Bertens, in her third match back from Achilles surgery, was knocked out by Russian qualifier Ludmilla Samsonova 6-2 6-1 inside an hour.

Fourth seed and last year's Australian Open champion Kenin responded after losing the first set to defeat Andrea Petkovic, winning 6-7 (6-8) 6-1 6-3. The match was Kenin's first since appendix surgery.

Sixth seed Pliskova comfortably got past Zheng Saisai 6-2 6-1 and 2019 US Open champion Andreescu triumphed over Tereza Martincova 7-6 (7-5) 6-2.

Seeds Elena Rybakina, Kontaveit, Maria Sakkari, Ons Jabeur and Amanda Anisimova all won, with 20th seed Petra Martic and Sloane Stephens both knocked out.

Ash Barty completed a great escape to stay alive at the Miami Open, where Simona Halep also progressed.

Barty faced a match point but the defending champion and world number one dug deep to prevail in three sets against Kristina Kucova on Thursday.

Romanian third seed Halep also needed three sets at the WTA Premier tournament in Miami.

BARTY PRODUCES COMEBACK

In her first match outside of Australia in more than 12 months, Barty survived to top qualifier Kucova in Miami.

Barty trailed 5-2 in the third set, with Kucova earning a match point at 5-3 but the Australian star saved it and won the final five games of the match to secure a spot in the round of 32.

Winner of the 2019 French Open, Barty sent down an equal career-high 15 aces in two-and-a-half hours.

"Today was really hard work, and I enjoyed every single minute of it," Barty said on court post-game. "There’s nothing like coming through a test like that, and now I get another opportunity in a couple days' time to play another tough match and test myself again."

Next up for Barty is 2017 Roland Garros champion Jelena Ostapenko, who outlasted Kirsten Flipkens 6-2 5-7 6-3.

HALEP REACHES MILESTONE

Halep brought up her 400th WTA main-draw triumph with a 3-6 6-4 6-0 victory over France's Caroline Garcia.

After dropping the opening set, Halep won 11 of the final 12 games to move through to the next round.

Halep won in one hour, 48 minutes, drastically improving on her first serve after the opening set while coming to grips with Garcia's kick serve.

"I needed time to get used to it and to get the rhythm," Halep said about Garcia's serve having improved her head-to-head record to 7-1, with Anastasija Sevastova awaiting in the last 32 after eliminating American sensation Coco Gauff.

Halep received attention on her shoulder early in the second. "I struggled with my serve," Halep said. "I struggled with my shoulder a little bit, so the attention was a little bit on the pain. [After that] I started to relax myself."

KERBER'S DOUBLE BAGEL

Three-time grand slam winner Angelique Kerber has been up and down in recently, but she flexed her muscles with a 6-0 6-0 humiliation of Renata Zarazua.

Aryna Sabalenka – the seventh seed – was another one to fend off match points before rallying 0-6 6-3 7-6 (11-9) past Bulgarian qualifier Tsvetana Pironkova in a gutsy.

Last year's French Open champion Iga Swiatek knocked off Barbora Krejcikova 6-4 6-2, while ninth seed and two-time Wimbledon champion Petra Kvitova got past Aliza Cornet 6-0 6-4.

Fifth seed Elina Svitolina survived to beat Shelby Rogers 3-6 7-5 6-3 and two-time major winner Victoria Azarenka benefited from a walkover.

Sloane Stephens ended her losing run to start the year with a hard-fought three-set win over France's Oceane Dodin in the first round of the Miami Open on Wednesday.

Former US Open champion Stephens, ranked 49th in the world, defeated Dodin 6-7 (6-8) 6-4 6-2.

Stephens progresses to the second round where the top seeds, including top three Ash Barty, Naomi Osaka and Simona Halep, will be introduced and she will face 28th seed Amanda Anisimova.

Danielle Collins, Wang Qiang, Alize Cornet and Caroline Garcia were among the other winners on Wednesday, while Svetlana Kuznetsova bowed out.

SLOANE FIGHTBACK

Stephens had endured a dismal start to 2021, enduring an 0-4 win-loss record to begin the year.

The 28-year-old American was made to do it the hard way against Dodin on Wednesday, dropping the first set in a tie-break.

Stephens improved on her return in the second set, winning 73 per cent of points off Dodin's second serve before running away with the match in the last.

"It's been a rough one for me lately, so I'm really pleased to get through that, fight my way through it and make it happen somehow," Stephens said post-match.

FORMER MAJOR WINNER GONE

Two-time grand slam winner Kuznetsova was the major first-round casualty, going down 2-6 6-2 6-1 to France's Alize Cornet.

Kuznetsova, who is now ranked 35th in the world, bows out with Cornet to face ninth seed Petra Kvitova.

Collins got past France's Kristina Mladenovic 6-3 6-3 with the 40th-ranked American setting up a second-round clash with 32nd seed Veronika Kudermetova.

Wang, ranked 38th in the world, also progressed despite dropping a set in a 6-1 3-6 6-3 win over Spanish qualifier Aliona Bolsova.

SECOND-ROUND MATCH-UPS

The round of 64 will commence on Thursday, with third seed Halep to face Garcia who got past another Romanian, Mihaela Buzarnescu 6-1 6-2.

Top seed Barty will be in action against Slovakia's Kristina Kucova, while fourth seed Sofia Kenin will take on former top-10 player Andrea Petkovic.

Second seed Osaka has an assignment against 77th-ranked Australian Ajla Tomljanovic, while 14th seed Victoria Azarenka is already into the third round with opponent Laura Siegemund withdrawing after her win on Tuesday.

Three-time champion Venus Williams was dumped out of the Miami Open on Monday in straight sets by Kazakhstan's Zarina Diyas. 

Diyas, ranked 89th in the world, had lost her only previous match against seven-time major winner Williams, but saw off the American 6-2 7-6 (12-10).

"I'm very happy with the win, it was very tough," Diyas said after her victory. "Venus, I looked up to her when I was little, she's such a legend. So for me, it's a really special win."

Elsewhere, Shelby Rogers overcame fellow American Madison Brengle 6-3 6-3 to set up a second-round clash with fifth seed Elina Svitolina.

"I'm really happy to get through that one, she's a really tricky player," Rogers said. "It's actually my first win at this site. The last time I was here, I was spectating, as an injured person! So I'm very happy to be here."

There were also wins for Magda Linette, Sorana Cirstea, Barbora Krejcikova and Kaia Kanepi, while Ajla Tomljanovic beat Anastasia Potapova to seal a clash against second seed Naomi Osaka in the next round.

Canadian teenager Leylah Fernandez celebrated her maiden WTA Tour title after winning the Monterrey Open in straight sets.

Fernandez broke through with a comfortable 6-1 6-4 victory over qualifier Viktorija Golubic on Sunday.

Featuring in her second WTA final after losing last year's Mexican Open in Acapulco, the 18-year-old Fernandez ensured she got her hands on the trophy this time.

Fernandez did not drop a set throughout the WTA International tournament, easing past her Swiss opponent in one-and-a-half hours.

Daria Kasatkina claimed the fourth title of her career after Margarita Gasparyan retired in the second set of the St Petersburg Ladies Trophy final with a back injury.

Kasatkina, who becomes the first player to win two WTA tournaments in 2021 having claimed the Phillip Island Trophy last month, was leading 6-3 2-1 when Gasparyan pulled out.

Gasparyan initially took a medical timeout after losing her first two service games of the match to trail 4-1 before eventually retiring after dropping her serve early in the second set.

Kasatkina's triumph meant she became the first player to win both WTA 500 events on Russian soil, previously claiming the 2018 Moscow title at this level.

The former top-10 player has endured a dip in recent seasons but will be back in the top 50 on Monday, while wildcard Gasparyan's maiden WTA 500 final means she returns to the top 100.

Kasatkina dropped the opening set in her quarter-final and semi-final matches but then swept through the next two sets emphatically on each occasion.

"I'm proud of how I was able to manage the pressure," Kasatkina said, quoted on the WTA website. "I felt differently during this tournament and I'm really proud of that."