Second seed Sorana Cirstea breezed through the first round of the Istanbul Cup on Tuesday as US Open champion Emma Raducanu prepares for her bow in the Porsche Tennis Grand Prix.

The Romanian made short work of lucky loser Kamilla Rakhimova in a 6-4 6-1 straight sets victory in Turkey to launch her defence of the title she won against Elise Mertens last year.

The Belgian – top seed once again in Istanbul – gets her campaign underway against Sweden's Rebecca Peterson on Wednesday.

Elsewhere, there were wins for seeds Veronika Kudermetova and Jil Teichmann, though Tereza Martincova is out after a surprise 6-4 7-5 loss to qualifier Anna Bondar.

World number 12 Raducanu meanwhile is also poised to get her latest tilt for silverware underway in Stuttgart in midweek, with the eighth seed facing qualifier Storm Sanders.

The title is up for grabs on the WTA Tour following Ash Barty's retirement, with her world number one successor Iga Swiatek a potential quarter-finalist for the Briton if she gets that far.

There will be no Coco Gauff in the mix however after the American made a first round exit in straight sets, losing to Daria Kasatkina 6-4 6-2.

Seventh seed Ons Jabeur, meanwhile, fought back to beat Marketa Vondrousova 4-6 6-2 6-3, while qualifier Eva Lys overcame Viktorija Golubic 5-7 7-5 7-5 to set up a second round clash with Swiatek.

Emma Raducanu has revealed the responsibility for her new-found affinity for Tottenham lies predominantly with her Spurs-obsessed support team.

Social media has been abuzz on Monday with photos and videos of the 19-year-old US Open champion training in a Tottenham jersey ahead of the Stuttgart Open.

The shirt even had her name and the number 10 emblazoned across the back, suggesting a particularly strong connection with the north London club. But it is not quite as it seems.

Raducanu, who was born in Toronto but raised in south-east London, said she has been heavily influenced by those close to her – although the presence of star duo Harry Kane and Son Heung-min was also a consideration.

"My whole team basically are big Spurs fans and I feel like they're egging me on," Raducanu told reporters.

"They're desperately trying to get me behind them! I don't necessarily follow football much, but I feel like now, because of them, I'm feeling some sort of connection.

"I loved following the Euros last year and watching Harry Kane, who's obviously the England captain, and Son, I'm a big fan of him as well. So yeah, I like to dabble."

Raducanu is seeded eighth for her first-ever tournament on clay this week and will begin her campaign against Storm Sanders on Wednesday.

While Raducanu's immediate aim is undoubtedly building momentum, she sees this tournament as a chance to make a statement on a surface she believes will be her strongest in the long term.

"It's going to be an exciting clay season," she added. "I'm not sure how it is going to go. I keep telling everyone around me that one day clay is going to be my surface and I still believe that.

"I think game-wise on clay, especially when you're playing outside, you definitely need to be a lot more patient and build the point.

"You can't just hit a big shot, whereas on a hard court, you might be able to get a weak shot straight away. You really need to build the point a lot more, which takes a lot more energy and physical demand.

"You just have to be more crafty, I think, and I think it's a good lesson, especially for someone younger like me, to develop more skills. 

"I'm looking forward to spending more time on the clay as the years go by because I do like sliding and moving on it, and it's just about again being able to repeat over and over."

There were two first-round matches played in Stuttgart on Monday, with Liudmila Samsonova claiming a double bagel when beating Chloe Paquet 6-0 6-0, while Ekaterina Alexandrova defeated Shuai Zhang 7-6 (7-5) 7-6 (8-6).

Kim Clijsters has called time on her latest tennis comeback, announcing her retirement from playing in official tournaments.

The Belgian surprisingly stepped away from the sport in 2007, before returning in 2009 to win back-to-back US Open titles in 2009 and 2010 before being crowned the 2011 Australian Open champion.

Clijsters retired again after the 2012 US Open, where she was beaten in the second round, before returning in February 2020 at the age of 36.

The former world number one's first match in over seven years came at the Dubai Duty Free Tennis Championships, losing in straight sets to Garbine Muguruza, while her last official match was in October, when she was defeated by Katerina Siniakova in the first round at Indian Wells.

Clijsters took to Instagram on Tuesday to announce her decision, posting: "I want to share with you that I have decided to no longer play official tournaments. I can't wait to see what new adventures will cross my path. Thank you to everyone who has supported me over the past two years!"

Mother of three Clijsters revealed stepping away from tennis again had "been on my mind for a while."

"I still love to hit the ball," she told the WTA website. "With my schedule, three, four days was enough to keep my rhythm under control but definitely not good enough if I decided to play another tournament. Say, if I picked Australia, it's three, four weeks. That's just not possible at this stage in our family life.

"Life just sort of takes over, right?"

Clijsters won three US Open singles titles in all, as well as her Australian Open crown, and in 2003 won both the French Open and Wimbledon doubles titles with Ai Sugiyama.

She became world number one on four separate occasions, winning 41 overall titles and boasting a career match record of 523-131 (80.0 per cent).

Belinda Bencic continued her strong run of form in the United States as she defeated world number 10 Ons Jabeur 6-1 5-7 6-4 to win the Charleston Open.

Sunday's success made it 10 victories from her past 11 matches for Bencic, with the lone defeat coming in a semi-final against Naomi Osaka at the Miami Open.

The Swiss Olympic gold medallist flew out of the gates in the opening set, winning 80 per cent of her points on serve (16 of 20) and breaking Jabeur twice.

It was a far more competitive second set as Jabeur's return game improved, the Tunisian also saving six of eight break points to force a decider.

Bencic prevailed in a rollercoaster of a third set, where Jabeur converted two breaks of serve, but the eventual champion managed three, finding a response every time she was challenged.

Jabeur becomes the second top-10 scalp claimed by Bencic this tournament after also defeating world number three Paula Badosa in three sets in the quarter-finals.

Germany's Tatjana Maria sank the hopes of Brazil's Laura Pigossi by carrying off the Copa Colsanitas title in Bogota, landing a 6-3 4-6 6-2 victory in Sunday's final.

Maria, who won her only previous WTA singles title in Mallorca in 2018, had the serving advantage in a contest between two qualifiers, hitting six aces to Pigossi's zero.

In the two sets that she won, Maria won 80 per cent of her successful first serves (28 of 35), not allowing Pigossi a look at a break point in the opener and saving two opportunities in the third.

Maria won seven matches in nine days while at the event in Colombia, with the 34-year-old dropping only two sets in the process.

The win will see a significant jump in Maria's world ranking, which is currently number 237 after taking time off to have a child.

Belinda Bencic wondered if she would ever be able to compete for titles on clay but will do exactly that on Sunday.

The Swiss reached her first ever WTA Tour final on the red dirt of the Charleston Open, beating semi-final opponent Ekaterina Alexandrova 6-4 6-3.

Although she has four WTA titles to her name, this was only Bencic's third last-four appearance on clay – losing the prior two, including a 2014 Charleston challenge as a 17-year-old.

But she finally has glory in her sights, and the omens are good for the final, facing Ons Jabeur having won their only prior meeting in 2021 at the Madrid Open, another clay-court event.

"I'm happy this moment came," Bencic said. "I didn't think it would, but I'm super happy with how I played today. I thought it was a great match in tough conditions."

Bencic needed only 78 minutes to complete the job, but Jabeur found life tougher, forced to rally from a set down to Amanda Anisimova.

The 20-year-old American had herself recovered to eliminate top seed Aryna Sabalenka earlier in the tournament but was now on the wrong side of such a comeback.

Jabeur, who lost in the final of the WTA 250 Charleston Open II last year, prevailed 2-6 6-1 6-4.

Meanwhile, at the Copa Colsanitas, there will be no repeat win for Camila Osorio after the defending champion and top seed lost to Laura Pigossi in straight sets in the semis.

Tatjana Maria is now Pigossi's opponent in the title match.

Belinda Bencic has beaten world number three Paula Badosa 2-6 7-6 (7-2) 6-4 to move on to the semi-finals of the Charleston Open.

Bencic, the 10th seed, appeared overmatched early on as she won less than half (12-25) of her service points in the opening set, getting her serve broken twice.

But as Bencic found her rhythm with her serve – winning 77 per cent of her first-serve points in the second set (24-31) – she wrestled the momentum away from Badosa, dominating the tie-break before breaking in the opening game of the third frame.

Bencic will face Ekaterina Alexandrova in the semi-final after the Russian dominated Magda Linette 6-0 6-2.

For the match, Alexandrova won 62 per cent of her points on serve (28-45) and 62 per cent of her points on return (26-42).

Fourth seed Ons Jabeur needed just 64 minutes to get the job done 6-3 6-2 against Anhelina Kalinina, winning 81 per cent of her successful first serves (29-36).

Jabeur will play 15th seed Amanda Anisimova in the semi-final after the American cruised past compatriot Coco Vandeweghe 6-1 6-2.

It was not a perfect performance from Anisimova, but she saved all five break points that she faced to never allow her opponent to get close.

Meanwhile, in Bogota at the Copa Colsanitas, top seed Camila Osorio is through to the semi-final after defeating Elina Avanesyan 6-1 6-4, where she will meet Laura Pigossi.

Karolina Pliskova believes Ash Barty could return to tennis following her surprise retirement in March, but the Czech acknowledged she could not relate to the decision as she "likes the game too much".

Barty became just the second player to call quits on their playing career when ranked as world number one, after Justine Henin, with a shock announcement last month.

The 25-year-old cited a lack of "physical drive and emotional want" to compete despite claiming her second grand slam title at the Australian Open just two months before.

However, just as Henin did after retiring, former world number one Pliskova has a feeling that Barty, who defeated her in the 2021 Wimbledon final, may also return to the court in future.

"I was shocked because I'm not really on Twitter because I don't want to get too much information for myself," Pliskova told the WTA on Barty's retirement.

"But somebody messaged me and said, 'Oh, did you see the news?' It was 11:00 in the evening in Miami. I was like, 'No, no, did somebody cry again or something?' They said, 'No, no, Ashleigh, she stopped.' I'm like, 'No way, that's not possible. Tell me the reason.' 

"I understand everybody's different. For me, it's not understandable at all because I just like the game so much. But I understand somebody maybe suffers, somebody doesn't like to travel.

"She basically won everything that she wanted to win, I suppose maybe she had no motivation. If you hate this tennis life and it's not what you always wanted to do, I think it's good to stop. 

"But I was surprised and shocked. I thought she was a really good number one for our sport and she was there for a while. Of course now, Iga [Swiatek] is a really good player, but I just thought Ashleigh was a good person and she had good charisma. I'm going to miss her. 

"But you never know. I think maybe she's going to come back. And then she's just going to be 27."

Meanwhile, Pliskova is focusing on her comeback as she continues to recover from a freak gym accident that resulted in a broken arm, which delayed the start of her new campaign by two months.

The 30-year-old, who has reached two major finals, made an encouraging return as she defeated Ukraine's Katarina Zavatska at Charleston Open but fell to Ekaterina Alexandrova on Friday.

"It was tough because people who follow tennis or me, they know I don't really have injuries," she added. "Even if I feel something, I still play. I never skip anything, not even practice or a tournament.

"The only break I had was this Covid break and I don't think that helped me. This injury was a bit more serious because I could not use my arm. I had a cast for a month or two. So it was quite a difficult time.

"I think things are going quite well. I just try to take the positives out of it, that I'm able to play after a couple months. It's been too long for me because with the offseason together, I missed four or five months.

"I know I'm not the player which can have five months at home and then I come in and win a tournament. I need some time to go through the feelings and the matches. I know it's going to take time, but just happy to be back."

World number five and the tournament's top seed, Aryna Sabalenka, was upset by American Amanda Anisimova 3-6 6-4 6-3 in the third round at the Charleston Open.

Sabalenka's serve was the key to her early success, connecting on 73 per cent of her first serves, and winning 15 of the 19 points in that situation (79 per cent).

When Sabalenka's first serve percentage fell to 48 in the second set, Anisimova found her footing, breaking twice in the frame, before pouncing on the Belarusian's lacklustre second serve in the deciding set, winning seven of nine opportunities to earn the break and the win.

Sixth seed Jessica Pegula was also bounced in surprising fashion, losing 6-4 3-6 6-4 to unseeded compatriot Coco Vandeweghe.

In a razor-close contest, it came down to who took their chances, as Vandeweghe saved seven of the 10 break points she faced, while Pegula could only save one of five.

World number 10 Ons Jabeur had no problem navigating the challenge of Emma Navarro, winning 6-3 6-2 as she broke her opponent's serve on six occasions.

Canadian seventh seed Leylah Hernandez also fell victim to an unseeded upset, going down 3-6 6-3 6-4 against Poland's Magda Linette.

In a meeting between two top-10 seeds, Belinda Bencic got the better of Madison Keys to edge it 6-4 6-4.

Second seed Paula Badosa had to come from a set down to eventually get the better of Claire Liu 3-6 7-6 (10-8) 6-1.

In the late session, French 12th seed Alize Cornet went down in a close tussle against Ukraine's Anhelina Kalinina 7-6 (7-5) 7-5, while Jabeur won her second match of the day, beating Irina Begu 6-3 6-2.

Meanwhile, in Bogota at the Copa Colsanitas, top seed Camila Osorio dispatched Turkish opponent Ipek Oz 6-3 7-6 (7-4) to move on to the quarter-final where she will meet Elina Avanesyan.

Serena Williams appeared to shut down premature talk of calling time on her career by declaring that she hopes to return from injury in time for Wimbledon.

The 40-year-old has not played competitively since losing to Aliaksandra Sasnovich in the first round of last year's tournament at SW19 and is now ranked at 246 in the world.

Williams' future in the sport was called into question on Thursday when her long-time coach Patrick Mouratoglou announced he will now work with Simona Halep.

However, the 23-time major winner – who has been coached by Mouratoglou since 2012 – has moved to confirm her intention to return to top-level tennis in the coming months.

Speaking alongside Green Bay Packers quarterback Aaron Rodgers at an event in Miami, Williams said: "We've been talking about my comeback and he's been hyping me up.

"He's getting me ready for Wimbledon. Can't wait!"

Williams is one major title shy of matching Margaret Court's long-standing record of 24, having been beaten in four finals since her most recent triumph at the 2017 Australian Open.

She missed last year's US Open on home soil, as well as the 2022 Australian Open in January.

Rodgers was surprised at Williams' Wimbledon announcement and asked: "What about the US Open?", to which the ex-world number one replied: "Wimbledon is first".

The grass-court grand slam gets under way on June 27.

Patrick Mouratoglou, the long-time coach of Serena Williams, has confirmed he will now work with Simona Halep.

Mouratoglou began coaching Williams in 2012 and has guided the former world number one to 10 grand slam titles and a further six major finals.

However, the last of those triumphs came in 2017, with Williams still one major success shy of matching Margaret Court's long-standing record of 24.

Williams reached the semi-final of last year's Australian Open, losing to Naomi Osaka, before subsequently going out in the last 16 at Roland Garros.

But the 40-year-old has not featured since retiring due to an injury in the first round to Aliaksandra Sasnovich at Wimbledon and is now ranked as the world number 246.

And it does not appear as though Williams will be making a return to the WTA Tour soon, with Mouratoglou explaining that, at least in the short term, he will be coaching former world number one Halep.

"Today, I am starting a new chapter in my coaching career: I am now the full-time coach of Simona Halep," Mouratoglou tweeted on Thursday.

"In the last eight months, I realised how much I missed coaching. It is the passion of my life, and I still feel like I have so much to give.

"Simona came to the Mouratoglou Academy before Indian Wells for a training block. I swung by at a few of her practices, watched her train.

"At the end of the week, she asked me if I was available to coach her. I have the highest respect for her but it was out of the question at the time.

"A few weeks later. I had a conversation with Serena, and the door opened for me, at least short term, to work with someone else.

"I will keep you updated on what's coming next soon."

World number 20 Halep endured an injury-hit 2020 and 2021, and split with long-time coach Darren Cahill in September of last year. The Romanian has won two grand slam titles, triumphing at Roland Garros in 2018 and Wimbledon the following season.

She has reached three other major finals and enjoyed a strong start to 2022, triumphing at the Melbourne Summer Set 1 prior to the Australian Open, in which she reached the round of 16.

Runs to the semi-finals at the Dubai Tennis Championship and Indian Wells Open have followed, though the 30-year-old will be hoping Mouratoglou can help her recapture the form she showed to end 2017 and 2018 on top of the WTA rankings.

Top-seeded Aryna Sabalenka won for the first time since late February, defeating Alison Riske 7-6 (7-3) 6-4 at the Charleston Open on Wednesday.

Losing her opening matches at the sunshine double of Miami and Indian Wells, after only taking five games off Iga Swiatek at the quarter-final in Doha, the world number five improved her head-to-head record with Riske to 5-0.

Sabalenka by no means cruised to victory, though, failing to close the match out at 5-2 in the second set. Riske had four break points to level at 5-5, but the 23-year-old powered through when she needed to, eventually closing out after an hour and 49 minutes.

Second-seeded Paula Badosa of Spain and ninth-seeded American Madison Keys also advanced to the third round at Charleston, with respective wins over Anna Bondar and Ulrikke Eikeri.

Badosa, who made the semi-finals in Charleston last year, overcame a mid-match rain delay to eventually win in an hour and 35 minutes.

Jessica Pegula continued her positive run of form after making the semi-finals in Miami, accounting for Jasmine Paolini with a 6-2 6-1 victory.

Other seeded winners included Belinda Bencic and Alize Cornet, while Elina Rybakina, Ajla Tomljanovic and Shuai Zhang were among seeds who lost on Wednesday.

The weather in South Carolina continued to be a problem at the first WTA clay-court event this season, however, as the match between Ons Jabeur and Emma Navarro was suspended due to heavy rain.

Meanwhile at the Copa Colsanitas in Bogota, Rebecca Peterson was the only seeded player in action on Wednesday, and lost 6-1 6-4 to Germany's Tatjana Maria.

Belinda Bencic survived a scare as she advanced to the Charleston Open second round with a 4-6 7-6 (7-5) 6-3 win over Wang Xiyu.

The Olympic gold medallist was a semi-finalist in Miami last time out, while she has also reached the quarter-finals in Sydney and St Petersburg this year.

However, the 10th seed was in danger of falling at the first hurdle at 5-2 down in the second set against world number 149 Wang.

Bencic rallied to force a tie-break and, subsequently, a deciding set, which she controlled to set up a second-round clash with 16-year-old Linda Fruhvirtova.

Magda Linette also fought back from the brink of defeat; the world number 64 saving a match point before prevailing against Maria Voleynets 4-6 6-3 7-6 (7-4).

Although, there was no joy for former champion Sloane Stephens, who was beaten in three sets by Zheng Qinwen.

Stephens – winner here in 2016 – recovered from losing the opening set 6-3 to take the second 6-4. But there was no denying the Chinese teenager, who dropped just nine points as she raced through the decider 6-0 to claim the first top-50 win of her career.

The likes of Jessica Pegula and Madison Keys were due to feature in the evening session, which was postponed due to severe inclement weather including the possible threat of a tornado.

In Bogota, top seed and home favourite Camila Osorio advanced to the last 16, but only after opponent Ylena In-Albon was forced to retire at 2-2 in the deciding set.

Fourth seed Hanna Udvardy and eighth seed Harriet Dart were beaten in straight sets by Dayana Yastremska and Elina Avanesyan respectively.

Alize Cornet was the highest seed in action on the first day of the Charleston Open, and showed her class, beating Alycia Parks 6-0 7-5.

Cornet, the 12 seed, was nearly perfect in the first set, winning 86 per cent of her service points (12-14) and 80 per cent of her return points (12-15).

15 seed Amanda Anisimova also made it through, and with an identical scoreline, defeating American compatriot Sachia Vickery 6-0 7-5.

China's Shuai Zhang is the 16 seed, and she also only needed two sets to see off unseeded opponent Francesca Di Lorenzo 6-2 6-4.

Hungary's Anna Bondar earned a second-round matchup against world number three Paula Badosa after defeating the Netherlands' Arianne Hartono 6-1 6-4.

Italian Jasmine Paolini will meet six seed and world number 13 Jessica Pegula in the second round after beating Romania's Gabriela Lee 6-2 6-3.

Meanwhile, in Bogota at the Copa Colsanitas, Brazilian qualifier Laura Pigossi defeated five seed Harmony Tan 6-4 6-3.

Top seed and world number 33 Camila Osorio will kick off her tournament on Tuesday against Ylena In-Albon.

Iga Swiatek has revealed she was "crying for 40 minutes" when she discovered Ash Barty had retired and the Polish sensation has felt "a range of emotions" after becoming world number one.

Barty sensationally called time on her career at the age of 25 last month.

The Australian quit while she was at the top of the rankings and on the back of winning her home grand slam for the first time at Melbourne Park in January.

Swiatek on Monday became Poland's first world number one and the 20-year-old could be hard to dislodge, as she is on a 17-match winning run.

The 2020 French Open champion became the youngest woman to win the Sunshine Double on Saturday when she beat Naomi Osaka in the Miami Open final after being crowned champion at Indian Wells.

Swiatek was in tears after finding out that Barty had ended her playing days and it soon sunk in that she would officially become the best player in the world.

She told BBC Sport: "I was crying for 40 minutes. Mainly, it was because of Ash's retirement. I didn't know it was going to happen and it really surprised me.

"I always had this vision that we would all play until we are 35 or something, until our bodies are so tired that we can't anymore.

"I needed time to actually understand what she must have thought. Her decision was really brave and I felt a lot of emotions because of that."

She added: "I also felt emotional because of my own position.

"I realised after two hours of being really emotional that 'hey, you don't know what is going to happen yet and you still have to win some matches'.

"So I told myself 'let's wait with the emotions and with being excited because I have work to do'."

Swiatek won the Qatar Open before claiming another two prestigious titles in the United States and the Warsaw native says the manner in which she has dominated has taken her by surprise.

"Emotionally it has been really intense and I have felt a range of emotions – from being proud and having satisfaction, to confusion and surprise," she said.

"These last weeks showed me I can trust in myself a little bit more and trust my skills and my tennis. Before I didn't really know it was possible for me to have a streak like that. So it also kind of surprised me.

"After Doha and after Indian Wells I didn't have time to digest what I've achieved. Right now I am going to take some time to analyse what happened from a 'work' point of view."