Serena Williams saw her hopes of an extended run at the Emilia-Romagna Open come to an early end on Tuesday, the top seed succumbing to Katerina Siniakova in straight sets.

Williams had taken up a wildcard to play in the tournament following an early exit in Rome, where she was beaten by Nadia Podoroska in her opening contest in the clay-court swing.

Her campaign in Parma got off to a better start on Monday, a 6-3 6-2 result against WTA Tour debutant Lisa Pigato bringing a first triumph since losing in the semi-finals of the Australian Open in February.

However, the 23-time grand slam champion was unable to repel a determined Siniakova as she slipped out at the last-16 stage.

"It was a fantastic match and I played so well, I'm so happy that I could finish like that," Siniakova said after recording a 7-6 (7-4) 6-2 result.

"It was a pleasure to share the court with her.

"Now I will have the pressure because I defeated a great player, but I will enjoy it. I'm happy that I can continue and I will try to play my best in the next match."

Having failed to convert a set point opportunity, Williams hit back after losing serve with a break of her own to force a tie-break in the opener.

But Siniakova forced her way into a 5-3 lead before sealing it with a service winner, then quickly seized control of proceedings in a second set which was far less competitive.

Third seed Coco Gauff came through two tie-breaks to see off Kaia Kanepi, the American teenager having let slip a 5-1 lead in the second set before eventually sealing a 7-6 (8-6) 7-6 (9-7) win.

Petra Martic had no such issues in her opening contest against Varvara Gracheva, the second seed easing through 6-4 6-2 after one hour and 21 minutes on court.

Serena Williams had no problems in her opening match at the Emilia-Romagna Open, but sister Venus was unable to join her in the last 16.

Top seed Serena eased to a 6-3 6-2 triumph over teenage qualifier Lisa Pigato in the highlight of Monday's action in the clay-court tournament, wrapping up the result in 68 minutes.

Pigato, 17, was making her debut in the main draw of a professional event having come through qualifying in Parma.

She enjoyed early success against the legendary Williams, too, claiming a break of serve in the opening game, but the 23-time grand slam champion soon got to grips with the task at hand.

"The first game, she played really good and I needed to adjust to get back," Serena said afterwards. "It was a bit of both, figuring out her game as well."

Next up for the American, who accepted a wildcard into the event after an early exit at the Internazionali BNL d'Italia in Rome last week, will be Katerina Siniakova, a 6-1 6-3 winner over Clara Tauson.

Venus, however, failed to make it beyond her opening outing, losing out to Anna Karolina Schmiedlova despite taking the opening set.

The Slovakian made it four wins in five meetings against the seven-time major champion, eventually prevailing 5-7 6-2 6-2 after two hours and 39 minutes on court.

Elsewhere, Sloane Stephens defeated fellow American Caty McNally in two sets, while seventh seed Sara Sorribes Tormo overcame Bernarda Pera 6-4 6-2.

There was also a win in straight sets for eighth seed Caroline Garcia, who got the better of Paula Ormaechea in a contest that saw both players serve impressively.

Garbine Muguruza eased into the second round of the Internazionali BNL d'Italia on Tuesday thanks to a comfortable victory over lucky loser Patricia Maria Tig, though Belinda Bencic was the biggest casualty on a rain-interrupted day.

Spaniard Muguruza was due to face Anastasia Pavlyuchenkova until the Russian withdrew due to an abdominal issue, giving Tig a reprieve and the chance of an upset.

But Muguruza won all but three games in a comprehensive 6-1 6-2 victory that required little more than an hour on court as the former world number one went to 22-6 for the season.

Conditions were not great as drizzle persisted for much of the match, but Muguruza was grateful to progress after a generally testing day.

"It was a weird day," the 12th seed said afterwards. "I woke up [and the weather was] sunny, had an opponent. Then it turned out I had another opponent and it was raining the whole match. We had a little bit of everything!

"But, Rome, it's such a familiar tournament. I played here so many times, I've had nice matches. I love this clay, the red clay. It's familiar to me. I'm just looking forward to getting as many matches as possible."

Bencic will not be joining her in the next round, as she became the highest seed to be eliminated on the day in a 6-3 6-4 defeat to Kristina Mladenovic.

The two played each other under two weeks ago in the first round of the Madrid Open, with Bencic victorious, but Mladenovic got her revenge as she capitalised on her opponent's seven double faults.

Like Tig, Sloane Stephens was also competing as a lucky loser as she came up against compatriot Madison Keys, though the outcome was no different.

Keys claimed only her second win in six meetings with Stephens but had to come from behind as she eventually clinched it 4-6 6-2 7-5 after two-and-a-half hours on court to set up a clash with 15th seed Iga Swiatek.

Elise Mertens, the 14th seed, was also dumped out of the competition, losing out 4-6 6-2 6-3 to Veronika Kudermetova, whom she had beaten in straight sets in their three WTA Tour contests before this one.

Veteran Kazakh Yaroslava Shvedova, ranked 665 in the world, awaits top seed Ashleigh Barty after the 33-year-old showed character to fight back and beat Martina Trevisan 0-6 7-6 (7-4) 7-6 (8-6), while Nadia Podoroska set up a second-round clash with Serena Williams after seeing off Laura Siegemund 2-6 7-6 (7-3) 6-1.

Jil Teichmann saved six match points in a stunning defeat of Elina Svitolina before Ash Barty breezed into the second round of the Madrid Open on Thursday.

Teichmann produced an astonishing fightback to beat fourth seed Svitolina 2-6 6-4 7-6 (7-5) at the Caja Magica.

Unseeded Swiss Teichmann came from a set and a break down to claim the scalp of the world number five, who squandered a commanding 5-1 lead in the final set.

Svitolina saw six match points come and go in an incredible deciding set, opportunities she was left to rue when the 40-ranked Teichmann won a tie-break to end a contest that took two hours and 33 minutes to settle.

World number one Barty extended her winning run on clay to 12 matches with a 6-2 6-1 success over Shelby Rogers.

Barty claimed her third title of the year in Stuttgart last weekend and the Australian needed just an hour to send Rogers packing, losing just two points on her first serve and not facing a single break point.

French Open champion Iga Swiatek was also an emphatic winner, easing past another American in the form of Alison Riske 6-1 6-1.

Swiatek, making her debut in this tournament, has won 16 consecutive matches on clay after blowing Riske away.

Defending champion Kiki Bertens beat 15-year-old Victoria Jimenez Kasintseva 6-4 6-0, while Petra Kvitova progressed when opponent Marie Bouzkova retired due to hand injury after the Czech won the first set.

Garbine Muguruza was forced to withdraw ahead of her meeting with Sloane Stephens due to a leg injury. Belinda Bencic, Angelique Kerber and Johanna Konta were among the other winners in the Spanish capital.

Ash Barty won her first match on clay since reigning supreme at the 2019 French Open as the world number one rolled into the Volvo Car Open round of 16.

Barty – who last featured in a clay-court match en route to Roland Garros glory almost two years ago amid the coronavirus pandemic – made light work of Misaki Doi 6-2 6-1.

Miami Open champion last week, top seed Barty continued where she left off at the WTA 500 event on Wednesday, closing out proceedings in just over an hour in Charleston.

"I had to use it as an opportunity to try and build some comfort," Barty said. "I think having a couple days between Miami and playing this first match was important, to have my body rest, but to also try and prepare to change surfaces. It was a very quick turnaround, but I felt great out there tonight."

Barty – who now boasts a 15-2 win-loss record in 2021 – will next face Shelby Rogers after she outlasted 13th seed Amanda Anisimova 1-6 7-5 6-4.

As for second seed Sofia Kenin, the 2020 Australian Open champion slumped to a shock 4-6 6-3 6-4 defeat against Lauren Davis midweek.

World number four Kenin – runner-up at last year's French Open – eased to the first set but fellow American Davis, ranked 79th in the world, changed tactics to fine effect.

"I was a bit uncomfortable so I just really dug deep and really started to think about how to beat her and I found that heavy deep balls were not her favourite," the 27-year-old Davis said.

"Being on clay, the ball bounces high, pushing girls back, so it's very effective."

Kenin took a medical timeout at 3-0 down in the deciding set but, despite reeling off the next three games, she was unable to see Davis off as her 2021 woes continue.

Davis now heads into another all-American clash with teenage sensation Coco Gauff – who came from 1-3 down in the third to defeat Liudmila Samsonova 4-6 6-1 6-4 in an absorbing two-hour contest.

Belinda Bencic – the fifth seed – crashed out as Paula Badosa claimed the first top-20 win of her career following a 6-2 6-7 (2-7) 6-1 success.

Badosa will face Caty McNally in the last 16 after the 19-year-old American beat Anastasija Sevastova 7-6 (7-3) 2-6 6-4.

Seventh seed Elise Mertens was another big name to depart as Alize Cornet prevailed 7-5 6-3, although 15th seed Veronika Kudermetova and 12th seed Ons Jabeur progressed in with the minimum of fuss.

Former US Open champion Sloane Stephens, meanwhile, topped eighth seed Madison Keys 6-4 6-4.

Seeds were even more vulnerable at the Copa Colsanitas in Bogata, including the top-seeded Saisai Zheng who was dispatched 6-4 6-1 by Stefanie Voegele.

Zheng's compatriot Yafan Wang, seeded eighth, went down 6-3 6-3 to Viktoriya Tomova.

Arantxa Rus and Jasmine Paolini, the third and sixth seeds respectively, lost in three to Spanish duo Nuria Parrizas Diaz and Lara Arruabarrena.

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.

Former US Open champion Sloane Stephens has continued her torrid start to 2021 after crashing out in the first round of the Monterrey Open on Tuesday.

Stephens went into the Mexico event as top seed but lost to Slovakian world number 151 Kristina Kucova 6-2 6-2.

The 27-year-old American is now 0-4 to start the 2021 WTA Tour season and has won only one set all season.

Stephens, now ranked 48th in the world, only managed to win 32.4 per cent of points on her first serve, with Kucova converting seven of 14 break points in the match.

Second seed Nadia Podoroska was also a first-round casualty on Tuesday, going down 6-4 6-4 to Russian qualifier Anna Kalinskaya.

In the late match, Eugenie Bouchard went down to China's Lin Zhu 7-5 7-6 (6-3).

One in eight women in the Australian Open draw have already won a grand slam title.

One in eight. It is staggering that of the 128 players who set out in the hope of singles glory at Melbourne Park, there are 16 major champions among them, and perhaps never has it been so difficult to predict who will carry off the title.

Compare it to the men's draw, where there are just five grand slam singles winners, and where you would struggle to make a compelling case for any more than three of those this year, with apologies to Stan Wawrinka and Marin Cilic.

As long-running dynasties near their end on the men's and women's tours, the WTA is a lengthy step ahead of the ATP with a cast of appealing characters already assuming leading roles.

The leader of the pack

Three-time grand slam champion Naomi Osaka is at the forefront of a school of rising stars, but she has impressive rivals for company.

The last four years have seen the 15 women's majors won by 12 different players, whereas in the men's game, Rafael Nadal (6), Novak Djokovic (5), Roger Federer (3) and Dominic Thiem (1) have creamed off all the top prizes in the same period.

Often criticised in the past for a perceived lack of depth, in the years when Serena Williams won seemingly at will, the women's tour has exploded with a rush of bright and young talent.

Osaka is a revelation and a leader, on and off the court. Twice a US Open champion now, and a winner in Australia two years ago, the 23-year-old Japanese star took a powerful stance for racial equality at Flushing Meadows back in September, at the height of Black Lives Matter protests. She wants to achieve even more off the court than on it, where she looks assured of one day leaving an impressive legacy.

If there is any area where Osaka's game falls down it is consistency. She has surprisingly not passed the fourth round in 14 of her 17 grand slam appearances, but on every occasion she has gone beyond that stage it has been en route to lifting a trophy.

In hot pursuit

Last year's three slam champions were, at the times of their triumphs, just 21 (Sofia Kenin - Australian Open), 19 (Iga Swiatek - French Open) and 22 (Osaka - US Open).

The women's game has not seen anything comparable in terms of youthful winners of its blue riband tournaments since 2004, when the 21-year-old Justine Henin won in Australia, Anastasia Myskina landed the Roland Garros title at 22, Maria Sharapova was a 17-year-old bolter to Wimbledon glory and 19-year-old Svetlana Kuznetsova scored a stunning Flushing Meadows victory.

Last year does not touch the 1997 season, when a 16-year-old Martina Hingis won the Australian Open, Wimbledon and US Open, denied a grand slam clean sweep by 19-year-old Iva Majoli's shock French Open final win over the Swiss.

But women's tennis is still seeing a remarkable shift to relative youth.

The 2019 season saw a then 19-year-old Bianca Andreescu scoop a stunning US Open win, while Ash Barty took the French Open.

Andreescu has been sidelined with a knee injury since the 2019 WTA Finals, but she is back for Australia, where Queenslander Barty, now 24, is the home hero.

Brace for the prospect of Andreescu and Barty joining Kenin, Swiatek and Osaka in a group of five who can take the women's game boldly into the post-Williams era.

But the Williams era isn't over

This is true, and again Serena will make another attempt to land that elusive 24th grand slam, the one that would move her level with Margaret Court on the all-time list.

She remains, at the age of 39, a magnificent competitor and a beguiling player, as does sister Venus, who turns 41 in June.

Serena has lost her last four grand slam finals, however, and the most recent run to a title match came almost 18 months ago in New York, where Andreescu had her number.

As the new gang of five threaten to pull away from the old establishment, perhaps Williams is now in the next group, along with the likes of Simona Halep, Victoria Azarenka and Petra Kvitova: still perfectly capable of winning another slam or even multiple slams, but it feels important to strike now.

Serena has not won any of her last 10 slams, making it the longest span in her professional career without winning a major.

Barty party, or Sofia the second?

Osaka begins the Australian Open as favourite with bookmakers, but world number one Barty will have home support and could make that count. How she performs will be keenly watched, given she chose not to travel once the COVID-19 pandemic hit last year, sitting out 11 months.

Should Barty get on a roll, hopes will be high she can become the first Australian woman to take the title since Chris O'Neil in 1978. Last year, Barty fell in the semi-finals to Kenin, and she will be eager to land a second slam title.

Kenin, whose intense concentration and steely resolve helped her pull off last year's shock Melbourne win, and follow up with a run to the French Open final, can be a match for anyone. She will be aiming to become the first woman to win back-to-back Australian Open titles since Azarenka in 2012 and 2013.

Success on this level has come perhaps ahead of schedule for the American, and the same can be said for Swiatek, whose demolition of the field at Roland Garros in October made a mockery of her being ranked number 53 in the world.

The teenage Polish player became her country's first grand slam singles champion, and with that status comes the expectation she will follow it up. How that turns out for her will be one of the most intriguing of sub-plots in the new season.

Changing priorities

Halep said in a recent WTA interview that winning an Olympic medal was her "main goal" for 2021, although Osaka will also have the Tokyo Games firmly circled in her diary.

For the likes of those other players among the 16 slam winners in the Melbourne draw, there will be differing targets this year, too.

Angelique Kerber, Sloane Stephens, Jelena Ostapenko and particularly Garbine Muguruza may yet come good again on the big stage at some point this season.

For Venus Williams, Kuznetsova and Samantha Stosur, it may be a case of one final hurrah.

As the likes of Coco Gauff emerge as potential future big-stage winners, and fledgling ambassadors, the women's game looks in safe hands.