Elina Svitolina said she "was on a mission" for Ukraine after earning a straight-sets win over Russian opponent Anastasia Potapova in the opening round of the Monterrey Open.

The top seed donned the yellow and blue colours of her homeland for Tuesday's match and eased to a 6-2 6-1 victory in a little over an hour in Mexico.

Svitolina only agreed to play her opener after tennis authorities announced a ban on Russian and Belarussian players competing under the name and flags of their countries.

And as Russia's invasion of Ukraine entered its sixth day, the 27-year-old produced an impressive performance that saw her win 73.5 per cent of her first-serve points.

Former world number three Svitolina, who will now face Bulgarian qualifier Viktoriya Tomova, had previously announced she will donate her prize money to the Ukrainian army.

"It's a special one because of what we are going through right now in Ukraine, it's terrifying," Svitolina told reporters. 

"It's been six days and all the Ukrainian tennis players and Ukrainians who are there, we have been really terrified with what is happening.

"For me, playing the match here, I'm not playing only for myself. I'm playing for my country, I'm playing for the help of the Ukrainian army and people in need. 

"I was focused. I was on a mission for my country. From the beginning, it was important to be ready for anything that comes my way."

Petra Martic is also through to round two after recovering from behind to beat third seed Madison Keys 4-6 7-6 (7-3) 6-3.

Marie Bouzkova awaits following the world number 81's 4-6 6-2 6-4 win against Sara Errani. Number eight seed Ann Li's participation in the tournament came to an end with a 6-2 6-1 loss to Wang Xinyu, who will now face Brazil's Beatriz Haddad Maia.

Australian Open semi-finalist Madison Keys was bundled out of the Abierto Akron Zapopan in Guadalajara on Monday after a shock three-set loss to Harmony Tan.

Frenchwoman Tan, who is ranked outside the top 100, toppled the second seed in one hour and 46 minutes, winning 6-4 1-6 6-1.

In a seesawing battle, Tan's shotmaking and deft touch was a highlight, helping her steady after emphatically dropping the second set, before winning the first five games of the final set.

The win was Tan's first-ever victory against a top 30 player, qualifying her for the second round where she will play China's Wang Qiang who won 6-2 6-1 over Lauren Davis.

American sixth seed Sloane Stephens did not have such problems in her first-round encounter with qualifier Brenda Fruhvirtova, triumphing 6-2 6-2.

The 14-year-old Czech had enjoyed a good qualifying run but was thwarted by the 2017 US Open champion in 58 minutes.

Fruhvirtova had become the youngest player to compete in a WTA Tour main draw match since Keys in April 2009 at Ponte Vedra Beach.

Fifth seed Nuria Parrizas Diaz bowed out 6-1 6-4 to Slovakia's Ana Karolina Schmiedlova in one hour and 10 minutes. Schmiedlova will face Anastasia Potapova who progressed 6-4 2-2 after Lesia Tsurenko retired.

Japanese seventh seed Misaki Doi also exited, going down 4-6 7-5 6-4 to Marie Bouzkova in the late match, setting up a second-round date with qualifier Lucia Bronzetti who edged American wildcard Caty McNally 6-7 (5-7) 6-3 6-3.

Zheng Qinwen was another seeded casualty, with the Chinese eighth seed going down 6-3 2-6 6-2 to Anna Kalinskaya.

Ash Barty is ready for "one last crack" on Saturday when she will bid to become a first home winner of the Australian Open women's singles in over 40 years.

The 25-year-old Queenslander powered through to the third grand slam final of her career with a clinical 6-1 6-3 win over Madison Keys on Thursday.

She is 2-0 for her past two finals in the majors, taking titles at the 2019 French Open and last year at Wimbledon, and has looked an unstoppable force in Melbourne.

That theory will be put to the test by Danielle Collins, the 28-year-old big-hitting American who dismantled Iga Swiatek's game in the second semi-final to reach a first slam final.

Barty is dialled in and up for the challenge, looking to land the title that was last won by an Australian when Chris O'Neil triumphed at the 1978 tournament.

"It's fun, it's brilliant to be playing in the business end of your home slam," Barty said in a news conference.

"Saturday's going to be a new experience for me. So I'll go out there and embrace it, smile, try and do the best that I can, and whatever happens, happens.

"It's been an incredible January and incredible summer for us, and I'm really looking forward to having one last crack here, to really go out and enjoy it."

Wendy Turnbull was the last Australian finalist in the women's singles, way back in 1980, and the scale of the achievement in ending the long wait is not lost on Barty, who has already won doubles and singles titles this month at the Adelaide International.

"To be in the finals weekend of your home grand slam is what a lot of Aussie players dream of," she added.

This is modesty, but Barty is now a long-standing world number one, and therefore anything but lifting the trophy would be a disappointment at this stage, with 27th seed Collins looking to spring what would be a major upset.

Barty said she was able to "play the match on our terms" against Keys, pointing to her on-court effort being a collaboration with her support team.

Keys was outplayed and her reflection on the experience of tackling Barty was blunt.

"It's tough, it sucks. She's just playing incredibly well," Keys said. "You have a game plan in your head, but she's just executing everything so well.

"She's serving incredibly well, so you don't get any free points on that; her slice is coming in so much lower and deeper than it was in the past, so it's hard to do anything on that; and then you try to play to her forehand and she can open you up there.

"She's so locked in and focused. I've played her a handful of times and this is easily the best I think she's ever been playing."

Barty, who dabbled with cricket before focusing on tennis, appears to have a work-life balance that would be the envy of many, finding it no problem to unwind once she leaves the gates of Melbourne Park. Enjoying the early Australian dominance in the women's Ashes has only brightened her mood.

"It's pretty easy for me. When I'm not here, I don't think about the tennis too much," she said. "I've got the women's Ashes to watch, which is brilliant, read a book, few coffees, and we're set."

The young Barty who first visited the Australian Open before hitting her teenage years, for a training camp, would stand in awe of the player she has become.

"I'd have been only 11 or 12 years old," she recalled. "To see how professional it was and to see everybody going about their business was really eye-opening.

"My first taste of it was in the juniors and I loved it. Being able to get a taste of that kind of lit the flame. You wonder what you can achieve."

Ash Barty continued her fairy-tale run at the Australian Open, crushing Madison Keys to become the first local woman to reach the singles final in 42 years.

The two-time grand slam champion continued her impressive form at Melbourne Park with a 6-1 6-3 victory over Keys on Rod Laver Arena on Thursday.

Barty, the world number one, became the first Australian woman to reach the singles final at the tournament since Wendy Turnbull in 1980.

She can become the first to win the title since Chris O'Neil in 1978 when she faces either Danielle Collins or Iga Swiatek in Saturday's final, which she will undoubtedly start as favourite.

Barty has dropped just 21 games on her way to the decider and the reigning Wimbledon champion was again ruthless against Keys, who lost her fourth grand slam semi-final in five such appearances.

The 25-year-old Barty settled well and broke the Keys serve in the opening game.

A powerful forehand created the opportunity before she delivered a cross-court winner off that wing to convert following a Keys drop shot.

Barty only made two first serves in her opening two service games yet did not lose a point.

Spurred on by a hopeful and enthusiastic home crowd, Barty's variety and depth – plus nine unforced errors in five games from Keys – helped her race into a 4-1 lead.

Keys finally won a point against the Barty serve in the sixth game, the Australian forced to save a break point before sealing the opening set in 26 minutes courtesy of a forehand return winner down the line.

The first real signs of nerves from Barty came in the fifth game of the second set, but she dug out a tough hold for 3-2.

Keys had settled, but Barty grabbed the break she was after in the sixth game with back-to-back forehand winners.

Barty looked calm throughout and that did not change as she served out the match in style, booking a spot in the final with a forehand winner.

DATA SLAM: Brilliant Barty on verge of ending Aussie wait

Barty has already ended one long wait – an Australian reaching the women's singles final at Melbourne Park.

She is a win away from ending another by becoming the first Australian winner of the men's or women's singles title in 44 years.

WINNERS/UNFORCED ERRORS
Barty – 20/13
Keys – 8/24

ACES/DOUBLE FAULTS
Barty – 5/0
Keys – 1/1

BREAK POINTS WON
Barty – 4/6
Keys – 0/2

Madison Keys is enjoying being the underdog after moving into the Australian Open semi-finals on Tuesday.

The American was too good for Czech fourth seed Barbora Krejcikova 6-3 6-2 in their quarter-final, played on a warm day in Melbourne.

Keys reached her fifth career grand slam semi-final, but first since the 2018 US Open.

Riding a 10-match winning streak after claiming just 11 victories in all of 2021, Keys is staying focused as her run continues in Australia.

"I honestly feel pretty neutral, to be completely honest with you. I have gone into every match thinking I can absolutely win any match that I'm out on the court," she said.

"I will say it's been kind of nice to be the underdog for the first time in a long time.

"It's really just not even in my head about winning and losing. It's really just going out, competing, trying to do what the game plan is.

"If that's not working going to Plan B. The rest is kind of not even getting into my brain."

The heat on Rod Laver Arena seemed to get to Krejcikova, the French Open champion taking a medical timeout late in the first set.

Krejcikova said she would learn a lot from her run after struggling with the heat on Tuesday.

"Today it was the heat with some physical conditions that started to bother me during after five games. I mean, from there on, you know, I just couldn't put it together," she said.

"Just still I didn't want to end it up. I wanted to finish match. I wanted to try to do my best. Yeah, I wasn't really able to do that. Still I think it's a really good experience and I can learn a lot from it."

Keys will play either Ash Barty or Jessica Pegula in the last four.

Madison Keys moved into her first grand slam semi-final since 2018 with a straight-sets win over Barbora Krejcikova at the Australian Open.

Keys overcame Czech fourth seed Krejcikova 6-3 6-2 in hot conditions on Rod Laver Arena on Tuesday.

After a hard-fought 50-minute first set, Keys handled the heat the better of the two, closing out a deserved victory.

The win booked Keys a first major semi-final since the 2018 US Open and fifth of her career, with either Ash Barty or Jessica Pegula awaiting her.

After claiming just 11 match victories in 2021, Keys is on a 10-match winning streak, although she was challenged by Krejcikova, particularly early on.

A pair of break points went begging for Keys in the second game before she dug herself out of a 15-40 hole to hold for 2-1.

Keys held after a gruelling 18-point fifth game, one which looked set to be hugely important, after saving four break points.

Another lengthy game followed as opportunities, this time for Keys, came and went before Krejcikova sent a forehand wide to hand the American a 4-2 lead.

Krejcikova took a medical timeout at 2-5, but there was no stopping Keys taking the first set in 50 minutes.

The unforced errors continued to come from Krejcikova and a tame backhand into the net handed Keys a break in the opening game of the second set.

Looking increasingly weary, Krejcikova was broken to love in the third game, although the French Open champion did get one of those breaks back immediately.

Krejcikova continued to fight, but Keys powered away, breaking for 5-2 on her way to the last four.

DATA SLAM: Keys lands top-five win

Keys, the 2017 US Open runner-up, held an 8-20 record against top-five ranked opponents, and 2-6 at grand slams, heading into her meeting with Krejcikova.

The American at least improved that record and deservedly so, getting the better of Krejcikova.

WINNERS/UNFORCED ERRORS
Keys – 27/21
Krejcikova – 12/28

ACES/DOUBLE FAULTS
Keys – 11/1
Krejcikova – 2/4

BREAK POINTS WON
Keys – 4/12
Krejcikova – 1/8

Coco Gauff reflected on a hugely disappointing Australian Open defeat as the two leading United States players exited the women's draw on day one in Melbourne.

Gauff is ranked 16th, closing on top American Sofia Kenin in 13th, but neither advanced to the second round on Monday.

The 17-year-old was stunned 6-4 6-2 by Wang Qiang in a sloppy display that included 38 unforced errors, with 21 in a second set in which she fell 5-0 behind.

Meanwhile, Kenin was beaten by compatriot Madison Keys, who came into the tournament in high spirits having won her sixth career title – and first since 2019 – at the Adelaide International 2. That run included a semi-final defeat of Gauff.

After her latest loss, Gauff said: "I think just everything disappointed me about today.

"I feel like in the pre-season I worked really hard, and I felt like I was ready to have a good run here. Today I just didn't perform well.

"I think there's a lot to learn from. I think I was playing a little bit tighter than normal.

"So I think next time coming into the first round of a slam, especially after a tough week before, I think I need to just play more free and focus on the moment."

Keys is playing with that freedom, eager to move on from a dismal 2021 in which she won only 11 matches.

"I'm not taking it quite as seriously, that's the biggest difference this year," she said.

Keys already has seven wins in eight matches in 2022, defeating fellow Americans in each of her past three outings.

Of the win over 2020 champion Kenin, she said: "At this point every first round is tough, but when you have to go up against a grand slam champion it's never easy.

"I think knowing that she was going to compete so well, I just had a really good mentality and attitude. I had a couple of opportunities I didn't really capitalise upon and I was able to reset and continue to play well.

"I had my first real run in a slam here, I missed last year, so absolutely ecstatic to be back in Melbourne. It would mean the world to have another run here."

Madison Keys overpowered Alison Riske to score a crushing win in Saturday's Adelaide International 2 final.

A 6-1 6-2 victory for Keys at Adelaide International 2 gave her a sixth WTA Tour title and a first since a stunning run in 2019 at Cincinnati.

Keys, who faces a tough Australian Open first-round clash against 2020 champion Sofia Kenin, showed her form is coming back after a lean spell.

The former world number seven has slipped to a lowly 87th in the rankings, but at the age of 26 she has ample time to climb back towards the top of the game.

This win moves her back into the top 60, with Elina Svitolina and Coco Gauff among the players Keys has fended off this week.

Keys said: "I'm really happy with how today went. There were a couple of opportunities where momentum could have switched, and I think I did a really good job of just regrouping and continuing to focus on my side of the court. Really happy to get a win."

Keys explained her mindset had been "dark" at times in 2021, with her appetite for tennis ebbing away.

She said: "Just knowing from what I was thinking about last year and the deep, dark pit of despair that I put myself into because of that, I don't want to go back to that. I don't want to let myself borderline hate being on the tennis court and hate competing. If I let myself think that way, that's where it goes."

Her motivation is on an upwards curve now, and results like this will help. Keys held serve throughout, did not face a break point, and broke Riske's delivery four times on the way to sealing victory in an hour and six minutes.

Quoted on the WTA website, Keys added: "I think the biggest takeaway is that things can switch at any moment. As long as you can continue to have the right mindset and keep going for things and keep working hard, things will get better if they're not going well, as long as you just have the right mindset and continue to have a good attitude about it."

Barbora Krejcikova saved seven match points on her way to beating Anett Kontaveit in a thrilling Sydney Tennis Classic semi-final on Friday.

The world number four prevailed 0-6 6-4 7-6 (14-12) in a match that went the distance and will take on Paula Badosa, who beat in-form Daria Kasatkina in the other semi-final.

Krejcikova had lost five in a row against top-10 players and was soundly beaten in the first set, but she held in the second and earned the only break in the ninth game to level up. 

That set up an incredible decider, which fourth seed Kontaveit led 6-5, but she could not take the first three of her match points as Krejcikova battled valiantly to force a tie-break.

Krejcikova felt her opponent's pain as she then squandered two match points of her own when leading 6-4. 

It appeared neither player wanted to win as two more match points went begging for Krejcikova and four for Kontaveit in what turned into a real classic.

But Krejcikova eventually took her fifth opportunity to see off Kontaveit and reach a sixth WTA singles final.

"I think from both sides it was a really, really tough match," Krejcikova said. "I think we played wonderful tennis. 

"It was very, very tight, and I'm really happy that I was able to hold the nerves better and that I won this match.

"I was just playing, just trying to fight for every single ball. When I had those match points down, I was just trying to figure out how to build up the point and how to win the point."

Badosa awaits Krejcikova in Saturday's final after beating Kasatkina in a match with far fewer twists and turns.

Competing in her second semi-final in as many weeks, it was similar disappointment for Kasatkina as she fell to a 6-2 6-2 loss.

French Open quarter-finalist Badosa hit 26 winners to Kasatkina's 12 and did not look back after winning 14 of the opening 16 points.

At the Adelaide International 2, meanwhile, it will be an all-American final as Madison Keys and Alison Riske advanced past Tamara Zidansek and Coco Gauff respectively.

Riske was given a walkover win against Zidansek, who withdrew with an abdominal injury, while Keys beat compatriot Gauff in three sets.

Daria Kasatkina reached her second semi-final in as many weeks with a straight-sets victory over Garbine Muguruza at the Sydney Tennis Classic on Wednesday.

The world number 26, who was defeated by Amanda Anisimova in the Melbourne Summer Set 2 semi-finals last week, beat second seed Muguruza 6-4 6-4.

Kasatkina held throughout the opening set, landing 67 per cent of her first serves, and saw the job through in the second despite a couple of early breaks for Muguruza.

It is the Russian's first win over a top-five opponent since beating Caroline Wozniacki at the 2018 French Open.

She will now face fifth seed Paula Badosa, who saw off Olympic gold medallist Belinda Bencic 7-6 (8-6) 3-6 6-3 in an entertaining match lasting two hours and 35 minutes.

The other semi-final in Sydney will be contested between Anett Kontaveit and Barbora Krejcikova, who advanced past Ons Jabeur and Caroline Garcia respectively.

Krejcikova proved far too strong for Garcia, prevailing 6-0 6-2 in 70 minutes, while Kontaveit was in action for just 43 minutes before being handed a walkover win in her match.

Jabeur had targeted "payback" against Kontaveit after her quarter-final opponent pipped her to the final WTA Finals spot in November, but injury cost her the chance to do so.

Having lost the first set 6-4, Jabeur – who eliminated Petra Kvitova in the previous round – felt unable to continue due to a lower back injury.

At the Adelaide International 2, three of the five Americans in action made it through to the semi-finals.

Alison Riske's clash with compatriot Madison Brengle ended early due to the latter retiring with the first set level at 3-3. Tamara Zidansek awaits Riske after beating Lauren Davis 7-6 (7-4) 7-6 (9-7).

Coco Gauff and Madison Keys will meet in the other semi-final, meanwhile, following victories over Ana Konjuh and Ludmilla Samsonova in two and three sets respectively.

Ons Jabeur eliminated Petra Kvitova from the Sydney Tennis Classic and immediately set her sights on "payback" against next opponent Anett Kontaveit.

World number 10 Jabeur had lost her previous four meetings with Kvitova, but she emerged victorious on Wednesday with a 6-4 6-4 win to reach the quarter-finals.

Jabeur recovered from 3-1 down in both sets at Ken Rosewall Arena and converted half of her six break points on her way to setting up a meeting with Kontaveit.

The two will resume their friendly rivalry after Kontaveit overcame Romanian qualifier Elena-Gabriela Ruse 6-3 6-1.

Jabeur lost out to Kontaveit for the last WTA Finals spot in November and is now seeking revenge in the final warm-up event ahead of the Australian Open.

"Anett is a great player. We had our moments last year," Jabeur said. "I told her, 'You're obsessed with me, you always follow me, so stop [smiling]'.

"I know the pressure is on me, not really on her. But maybe I can get some payback for last year."

Garbine Muguruza is also through to the last eight in Sydney thanks to a 6-1 7-6 (7-4) win against Ekaterina Alexandrova.

The two-time major champion will face Daria Kasatkina, who beat Elise Mertens 6-3 6-4, for a place in the semi-finals.

Third seed Barbora Krejcikova survived a brief fightback from Jaqueline Cristian to advance 6-1 7-5, meanwhile, and Paula Badosa beat home hope Ajla Tomljanovic 6-3 6-4.

There was disappointment for in-form Elena Rybakina, who thrashed Emma Raducanu on Tuesday but had to withdraw from her clash with Caroline Garcia with a thigh injury.

At the Adelaide International 2, Coco Gauff prevailed 6-3 5-7 6-3 in her battle of the teenagers showdown with Marta Kostyuk.

Gauff is one of five Americans in the quarter-finals along with Madison Brengle, Alison Riske, Lauren Davis and Madison Keys, who beat Tereza Martincova 6-1 6-3 to advance.

Former US Open champion Sloane Stephens had to come from behind to progress against Heather Watson after almost three hours in the Indian Wells Open first round.

Stephens, who is currently ranked 73rd in the world, having been number three on the WTA Tour in 2018, triumphed 6-7 (5-7) 7-5 6-1 over Watson in two hours, 50 minutes on Wednesday.

In a see-sawing match, there were six breaks in the opening set, as Watson got the edge early on Stephens' serve at the WTA Premier 1000 event.

Stephens steadied by claiming a late break in the second to level the match, before dominating the third set.

Playing at her 10th Indian Wells Open, Stephens won seven consecutive games after the match was 5-5 in the second set.

"After the first set, that was disappointing to lose that one, but I felt like it was a battle and I was still in the match," Stephens said. "I knew I had to keep fighting and that's what I did, and I'm just really pleased to have squeaked out a win here."

KEYS ON SONG IN OPENER

Former world number seven Madison Keys moved through to the second round with a 6-0 7-5 win over fast-finishing Estonian veteran Kaia Kanepi.

American Keys won 21 consecutive points as part of a streak where she clinched the first nine games of the match, withstanding Kenapi's late push.

Keys will take on Russian ninth seed Anastasia Pavlyuchenkova for a spot in the third round.

SAMSONOVA, MARTIC, ROGERS AND PUTINTSEVA PROGRESS

Liudmila Samsonova, who made the fourth round at Wimbledon earlier this year, needed more than two hours to get past Ukrainian qualifier Kateryna Kozlova 6-4 7-6 (8-6).

Samsonova will face countrywoman and 25th seed Veronika Kudermetova in the second round.

Petra Martic won through to take on second seed Iga Swiatek with a 6-4 6-4 victory over American wildcard Katie Volynets.

Ash Barty's US Open conqueror Shelby Rogers claimed her 25th win for the year, getting past Ukrainian Anhelina Kalinina 7-6 (7-2) 6-2, while Yulia Putintseva won 7-6 (7-2) 6-1 over experienced German Andrea Petkovic to set up a showdown with fellow Kazakh player and 13th seed Elena Rybakina.

Petra Kvitova was one of a handful of seeded players to take the court at the Western and Southern Open on Monday and came away victorious against a past champion of the event. 

The 11th-seeded Kvitova defeated 2019 Western and Southern winner Madison Keys 7-5 6-4 on a rain-plagued opening day of main-draw play at the tournament outside Cincinnati, Ohio. 

The Czech saved eight of nine break points against her serve while breaking Keys three times, and that was enough to pull out the victory. 

Kvitova's countrywoman Barbora Krejcikova, the ninth seed, made her singles debut at the WTA 1000 event with a 6-3 6-2 rout of Daria Kasatkina. 

Fifteenth seed Elise Mertens also was a straight-sets winner, taking down Nadia Podoroska 6-3 6-4, while 13th seed Jennifer Brady defeated Ekaterina Alexandrova 6-3 7-6 (7-3) in a match that finished shortly before 1 a.m. local time.

Though only Krejcikova was in action Monday, the field in Cincinnati includes nine of the top 10 players in the rankings, led by Ashleigh Barty and Naomi Osaka in their first appearances since the Tokyo Olympics. 

In other matches on the first day of play, Heather Watson defeated Aliaksandra Sasnovich 6-2 3-6 6-1, while Paula Badosa outlasted Petra Martic 4-6 6-4 7-6 (11-9) in a two-hour, 34-minute marathon. 

Yulia Putintseva breezed past Zhang Shuai 6-2 6-0, Jelena Ostapenko beat Tamara Zidansek 7-5 6-1 and Jil Teichmann downed Sorana Cirstea 6-2 6-0. 

Angelique Kerber beat Maria Sakkari 6-2 6-2, with Alison Riske matching that scoreline in a defeat of Leylah Fernandez.

Shelby Rogers won 6-4 2-1 when her countrywoman Danielle Collins retired with an injury. 

Karolina Muchova was a casualty in the first round of the National Bank Open as she was stunned by Oceane Dodin in Montreal on Monday.

The 14th seed was undone by the French qualifier despite Dodin sending down 10 double faults.

The 6-3 1-6 6-2 success was Dodin's first over a top-25 player this season.

Former U.S. Open finalists and 16th seed Madison Keys was also a first-round casualty, going down 6-3 6-3 to Canadian Rebecca Marino.

Toronto-born Marino, currently ranked 220th in the world, won in one hour and six minutes, converting four of her eight break points, while she saved four from five too.

However, there were no such problems for Ons Jabeur, the 13th seed strolling to a 6-1 6-3 victory over Clara Burel.

Eleventh seed Maria Sakkari also had a routine day, her opponent Marie Bouzkova unable to continue with Sakkari ahead 6-4 3-1.

An Olympic gold medallist in the doubles at Tokyo 2020, Katerina Siniakova had more to celebrate in the singles with a 6-1 6-3 win over long-time rival Jelena Ostapenko.

Elsewhere in the draw, Paula Badosa, Sorana Cirstea, Amanda Anisimova, Nadia Podoroska and Fiona Ferro all progressed.

World number 26 Madison Keys was one of three seeded players to be eliminated in the second round of the Silicon Valley Classic in San Jose on Wednesday.

The American third seed was beaten by China's Zhang Shuai 7-5 7-6 (7-5) in one hour and 39 minutes.

Keys sent down 7-1 aces but Zhang, ranked 51st in the world, was excellent on return, converting four of her 11 break points.

Fourth seed Daria Kasatkina was also in danger after losing the first set but rallied to win 3-6 7-5 6-3 over France's Caroline Garcia.

"It was a tough match. From my point of view, I think the level of the game was very good, and I'm really happy that I was able to turn the match in the second set," Kasatkina said in the on-court interview.

Ninth seed Alison Riske was emphatically beaten by Croatian Ana Konjuh 6-1 6-4 in one hour and 13 minutes, while sixth seed Petra Martic bowed out to Poland's Magda Linette 7-5 7-6 (7-5).