World number one Ash Barty survived a scare to reach the semi-finals of the Stuttgart Open with a 2-6 6-1 7-5 win over Karolina Pliskova.

The Australian started slowly in the quarter-final of the WTA 500 tournament on Friday as Pliskova broke her serve twice in taking the first set, before Barty hit back with three breaks of her own to force a decider.

Barty was two points away from losing on five occasions as world number nine Pliskova served for the match at 5-4 in the final set.

But she broke the Czech's resolve eventually, sealing victory when Pliskova hit the ball long after a baseline rally.

The win was Barty's eighth consecutive victory over a top-10 opponent and she said in a media conference afterwards that facing top players in the world brings the best out of her.

"When you come up against top-10 opponents, you have to go to that level above to be able to compete. They force you to bring your best," Barty said.

"With a lot of the girls in the top 10, we've had plenty of matches that have gone either way, different experiences, so each time I love that challenge of testing myself against the best."

Barty will face Elina Svitolina in the semi-finals after she saved two match points to claim a 6-7 (4-7) 7-5 6-2 victory over Petra Kvitova.

In the other half of the draw, Simona Halep breezed through to the semi-finals with a 6-1 6-4 win over Ekaterina Alexandrova.

Halep clinically closed out the first set, and although Alexandrova showed more fight in the second, the world number three did not allow her a route back into the match.

Halep will face Aryna Sabalenka following the Belarusian's 7-5 4-6 6-1 win over Anett Kontaveit.

In the Istanbul Cup, top seed Elise Mertens secured her place in the semi-finals with a 6-4 6-4 win over Katerina Siniakova.

Mertens will face Veronika Kudermetova who fought back from a set down to clinch a 2-6 6-3 6-3 win over Ana Bogdan.

The other semi-final will see Sorana Cirstea play Marta Kostyuk. Cirstea progressed after Fiona Ferro, trailing 6-4, retired through injury while Kostyuk beat Ana Konjuh 7-5 4-6 6-3.

Simona Halep started her clay-court season in style at the Stuttgart Open as she saw off Marketa Vondrousova in straight sets on Thursday.

Second seed Halep is hunting her first appearance in a Stuttgart final, and she looked in fine form as she took just 56 minutes to dismiss Vondrousova 6-1 6-3.

Vondrousova – the 2019 French Open runner up – had won both of her previous meetings with Halep, but on this occasion she was no match for the world number three, who has won every major European clay-court tournament other than Stuttgart.

"Starting the clay-court season makes me very happy and motivated, extra motivated actually," Halep said in a post-match news conference.

"I missed playing matches. I had a few weeks without an official match and it was kind of tough when I started the match, but my mind was strong enough just to give focus on what I have to play. So, I did it great and today it was a great match.

"I was a little bit nervous before the match because I played twice against her and she beat me every time.

"It is important for my mind, for my game, because the clay-court season is going to be very tough. Now this match gave me confidence that my level is high, and if I keep doing the same thing, I will be good."

Facing Halep in the quarter-finals will be Ekaterina Alexandrova, who defeated world number 12 Belinda Bencic, and joining them in the final eight is Elina Svitolina, who defeated Angelique Kerber 7-6 (7-4) 6-3.

Two-time Stuttgart champion Kerber and Svitolina had faced off 13 times before Thursday's contest, and the Ukrainian is now 9-5 up in that head-to-head tussle.

While Aryna Sabalenka also progressed, Karolina Pliskova teed up a clash with top seed Ash Barty by coming from behind to beat Jelena Ostapenko 6-7 (7-9) 6-4 6-3.

At the Istanbul Open, top seed Elise Mertens also needed three sets to forge a path into the last night.

Mertens had to show her mettle in a contest which lasted over two hours, but she eventually got the better of Viktorija Golubic 6-4 4-6 6-1.

Veronika Kudermetova also made the last eight, as did Ana Bogdan, who fended off Barbora Kreijcova, while Fiona Ferro defeated Vera Zvonareva.

Carla Suarez Navarro revealed on Thursday she has overcome Hodgkin lymphoma, and the Spaniard is set to resume her tennis career.

The former world number six revealed last September she would undergo six months of chemotherapy after being diagnosed with the rare cancer.

Suarez Navarro vowed at the time to show "positivity in the face of adversity" and the 32-year-old has now announced she is cured.

The 32-year-old posted on social media: "Another step forward. Today I finished my treatment and overcame Hodgkin lymphoma.

"Thanks to all for your warm messages. Every word of support gave me strength during the past few months.

"All my gratitude to healthcare professionals who take care of us every day. I'M CURED!"

Carla Suarez Navarro announced two years ago that the 2020 season would be her last on the WTA Tour.

However, the WTA said she decided to has abandon that plan and would return to action, confirming her entry for the French Open which begins on May 30 in Paris.

Athletes expressed relief and vowed to continue the fight for reforms after a jury in Minnesota found a former police officer guilty in the May 2020 death of George Floyd. 

Derek Chauvin was convicted of second-degree murder, third-degree murder and second-degree manslaughter on Tuesday, nearly 11 months after he knelt on Floyd's neck and back for more than nine minutes during an arrest. 

Floyd's death aged 46 sparked outrage across the United States, with athletes across multiple sports among those who called for justice. 

Tuesday's verdict in Minneapolis provided a measure of progress and sports figures, teams and leagues spoke out after the ruling. 

Basketball star LeBron James' reaction was among the most succinct as he tweeted simply: "ACCOUNTABILITY".

Boxing legend Mike Tyson tweeted: "Guilty. Justice served."

While similiar expressions of relief were common, most continued to lament the crime that sparked the case. 

"George Floyd lost his life, as many others have, unjustly. We can't forget that - that people are losing their lives," Brooklyn Nets head coach Steve Nash told reporters.

"On the other hand, it is a small gesture of justice and possibly hope for the future in that perhaps all the social justice movements - the NBA, the WNBA, the community at large - are really making an impact.

"I just hope that this is the type of statement by our justice system that gives hope and precedence for these type of verdicts to be the norm."

Petra Kvitova brushed aside Jennifer Brady as the defending champion cleared her first hurdle at the Stuttgart Open.

The Czech left-hander was the last winner of the German tournament, beating Anett Kontaveit in the 2019 final, with last year's event cancelled due to the pandemic.

Kvitova was handed a tough opening assignment against Australian Open runner-up Brady, but the American's streak of defeats since that Melbourne final defeat extended to three as Brady lost 6-4 6-3 in an hour and 32 minutes.

Two-time former Wimbledon champion Kvitova, seeded seventh, picked apart the Brady serve once in each set and fended off three break points across the contest to secure her last-16 place.

She was joined in the second round by powerful Belarusian Aryna Sabalenka, as the fifth seed scorched to a 6-2 6-2 win over China's Zhang Shuai.

Earlier, Ekaterina Alexandrova, Kontaveit, Anna Lena Friedsam and Laura Siegemund also went through to the last 16 of the WTA 500 event.

Meanwhile, Fiona Ferro caused a shock at the Istanbul Cup as she landed a 7-5 6-2 first-round win over former champion Petra Martic.

Martic, seeded second this year and ranked 21st in the world, landed the title in Istanbul in 2019 but was rolled over by French player Ferro in an hour and 45 minutes, in a match featuring seven breaks of serve.

Veronika Kudermetova followed her recent maiden title in Charleston with a nerve-jangling first-round win against Bernarda Pera, the fifth seed scrambling through 6-4 3-6 7-6 (7-4).

There was no such toil for top seed Elise Mertens, a 6-2 6-0 winner against Lara Arruabarrena, or for Daria Kasatkina, who dished out a 6-1 6-0 drubbing to Tereza Mrdeza.

Kasatkina is seeking her third title of 2021, having won previously in Melbourne and St Petersburg.

Anastasia Pavlyuchenkova bowed out of the WTA 250 event though, beaten 7-6 (7-2) 6-7 (8-10) 6-4 by compatriot Anastasia Potapova.

Belinda Bencic claimed her first win on clay since the 2019 French Open as she saw off teenager Nastasja Schunk at the Stuttgart Open.

The world number 12 eased to a 6-4 6-2 victory over the 17-year-old qualifier, who saved five match points in her final service game before Bencic closed things out.

"My love affair with clay is... I'm trying to improve myself on it," Bencic said after her first-round triumph.

"I think I'm getting better and I'm taking falls sometimes. I'm trying my best on this surface."

Maria Sakkari was similarly comfortable in progressing to the next round, hitting 24 winners as she dispatched Andrea Petkovic 6-2 6-2 on her debut at the tournament.

At the Istanbul Cup, four of the five scheduled matches were completed before rain stopped play with Anastasia Pavlyuchenkova and Anastasia Potapova level at a set apiece.

Eighth seed Wang Qiang fought back from a set down to beat Anastasia Gasanova 4-6 6-1 6-2.

There were also wins for Ana Konjuh, Katerina Siniakova and Viktorija Golubic.

Australian Astra Sharma scored a shock win over top seed Ons Jabeur in the final of the MUSC Health Women's Open, landing her first WTA Tour singles title.

The world number 165 made a slow start to the match but eventually overwhelmed Jabeur 2-6 7-5 6-1 in Charleston.

Having risen to 27th in the world rankings without a trophy to her name, the 26-year-old Jabeur looked to have an ideal opportunity to put that right.

Sharma recovered from the one-sided opening set to lead early in the second, and despite Jabeur getting it back on serve, the underdog surged ahead again to level the contest.

In her second WTA singles final and first for two years, Sharma went one step further than when she was runner-up in Bogota, racing through the deciding set as she swatted away Jabeur's threat.

Jabeur said the defeat was "very tough" to take, while Sharma said of her breakthrough week: "This has been an amazing event. I've really enjoyed playing here."

Ons Jabeur earned revenge on Danka Kovinic with a 6-3 6-0 hammering in the semi-finals of the MUSC Health Women's Open.

It was only a week ago the top seed was defeated by the same opponent on the same Charleston court at the same stage in the Volvo Car Open.

But a day on from needing just 45 minutes to hammer Nao Hibino 6-1 6-0, Jabeur required a little over 90 minutes to progress to Sunday's showpiece.

Jabeur is now 18-7 for the year, with only Garbine Muguruza holding more wins on the WTA Tour in 2021.

On the other side of the draw, Astra Sharma overcame Maria Camila Osorio Serrano 7-6 (7-5) 6-1.

It marks Sharma's second WTA final and her first in two years.

Top seed Ons Jabeur moved through to the MUSC Health Women's Open semi-finals after easing past Nao Hibino.

Jabeur – eyeing her first WTA Tour title – made light work of Hibino 6-0 6-1 in Charleston on Friday.

Next up for the Tunisian is high-flying Danka Kovinic at the WTA 250 tournament.

For the second week in a row, Kovinic reached the semi-finals in Charleston after taking down hometown favourite and third seed Shelby Rogers 7-5 6-1.

Maria Camila Osorio Serrano, who claimed her maiden singles title at the Copa Colsanitas in Bogota last week, was leading 6-4 1-0 when Clara Tauson retired.

Meanwhile, Astra Sharma defeated 15-year-old Czech Linda Fruhvirtova 6-4 6-3.

Ons Jabeur and in-form Maria Camila Osorio Serrano both progressed to the quarter-finals of the MUSC Health Women's Open.

Top seed Jabeur eased past American world number 313 Alycia Parks 6-4 6-0 in Charleston on Thursday.

Eyeing her first WTA Tour title, Tunisian Jabeur will face Nao Hibino for a place in the semi-finals.

Colombia's Osorio Serrano, who claimed her maiden singles title at the Copa Colsanitas in Bogota last week, rallied past Christina McHale 2-6 7-6 (7-2) 7-6 (7-1).

Osorio Serrano and Clara Tauson will go head-to-head in the quarters at the WTA 250 event.

Linda Fruhvirtova – the 15-year-old Czech teen – and Astra Sharma also advanced at the expense of Emma Navarro and eighth seed Madison Brengle.

Shelby Rogers booked her spot in the MUSC Health Women's Open quarter-finals, but fellow seeds Ajla Tomljanovic and Lauren Davis crashed out.

Following her third-round appearance at the Volvo Car Open, Charleston native Rogers moved through to the quarters of her second hometown tournament in as many weeks after easing past qualifier Claire Liu 6-2 6-2.

"I think I was due for a couple of tame matches," said third seed Rogers, who lost to world number one Ash Barty at last week's Volvo Car Open. "I've had quite a few mental battles over the last couple of months, so it's been nice to just take care of business in straight sets, get in and get out."

Next up for Rogers at the WTA 250 event is in-form Montenegrin opponent Danka Kovinic, who upstaged seventh seed Davis 6-1 1-6 6-3 on Wednesday.

Australian sixth seed Tomljanovic was swept aside by teenager Clara Tauson 6-1 6-4, while Nao Hibino beat Francesca Di Lorenzo 6-4 6-3.

Top seed Ons Jabeur advanced to the last 16 at the MUSC Health Women's Open, while Magda Linette was a casualty on Tuesday.

Jabeur – who reached the semi-finals of the Volvo Car Open – made a winning start at the WTA 250 event after toppling Stefanie Vogele 6-4 6-1.

The Tunisian won 88.9 per cent of her first serves to set up a clash with qualifier Alycia Parks – the latter eased past fellow American Grace Min 6-1 6-4.

However, second seed Linette crashed out at the hands of in-form Colombian Maria Camila Osorio Serrano.

Osorio Serrano, who claimed her maiden singles title at the Copa Colsanitas in Bogota last week, upstaged Linette 6-3 4-6 7-5.

Elsewhere, 15-year-old wildcard Linda Fruhvirtova – in just her second WTA main-draw appearance – progressed 6-2 6-7 (7-9) 4-4 after fourth seed Alize Cornet retired in the final set.

Third seed Shelby Rogers eased into the second round of the MUSC Women's Health Open while fifth seed Misaki Doi retired in a three-hour epic on Monday in Charleston.

World number 46 Rogers, who reached the last 16 at last week's Volvo Car Open in Charleston, proved too good for fellow American Caty McNally winning 6-0 6-1 in just over an hour.

Doi's match with countrywoman Nao Hibino lasted much longer, extending to three hours and nine minutes with the latter progressing in a walkover 7-5 5-7 6-6. Doi succumbed to cramps in the third set tiebreaker.

Seventh seed Lauren Davis defeated Coco Vandeweghe 7-6 (7-3) 6-4 in their All American battle while Australian sixth seed Ajla Tomljanovic cruised past Renata Zarazua 6-1 6-1 in the final match of the first day.

Eighth seed Madison Brengle also progressed in three sets past Natalia Vikhlyantseva and unseeded Dane Clara Tauson won 6-3 6-3 over Liudmila Samsonova.

Veronika Kudermetova became the first winner of the Charleston Open since Serena Williams to triumph without dropping a set all week.

The 23-year-old Russian crushed the hopes of Montenegrin rival Danka Kovinic in Sunday's final, landing her maiden WTA Tour title with a 6-4 6-2 victory.

It meant Kudermetova sealed a perfect tournament, winning all six of her matches without being taken to a deciding set, just as superstar and 23-time grand slam champion Williams managed in 2012.

World number 38 Kudermetova said, quoted on the WTA website: "All the matches were really tough. It's really tough matches for nerves, and the tennis part, but I'm really proud of myself that I can take the first title. I'm really happy.

"It means a lot. It shows me that I can play really well, that I can beat good players, and if I play like this and keep working, I think I can be in the top 10 or higher."

The Copa Colsanitas title went to Colombian 19-year-old Maria Camila Osorio Serrano, a former US Open junior champion who entered the tournament on a wildcard but came through the field to also grab a first senior singles title.

She sank the trophy prospects of Slovenian fifth seed Tamara Zidansek, with the world number 180 recording a 5-7 6-3 6-4 victory, describing her success as "unreal".

There will be no dream first WTA Tour final for Paula Badosa at the Charleston Open after she was defeated in the last four by Veronika Kudermetova.

Badosa claimed the biggest win of her career so far in the quarter-finals when she knocked out world number one Ash Barty.

But the 23-year-old, twice beaten in the semis at WTA 250-level events in the past year, came up short against 15th seed Kudermetova.

The Russian was clinical, taking four of her six break point opportunities in a straightforward 6-3 6-3 success.

Kudermetova had previously knocked out Sloane Stephens but will now be favourite against Danka Kovinic.

The underdog's straight-sets defeat of Ons Jabeur in the last four should ensure there is no complacency from Kudermetova.

In Bogota, 19-year-old wildcard Maria Camila Osorio Serrano will play for the title after swatting aside qualifier Harmony Tan 6-1 6-2.

The former top-ranked junior will have to negotiate fifth seed Tamara Zidansek, however, after she defeated Viktoriya Tomova 6-3 7-5.