Japan’s Naomi Osaka retired from her second-round match against Dalila Jakupovic in Birmingham with an abdominal problem.

Osaka, ranked 18th in the world, struggled on serve and lost the first set 6-3 before calling for the trainer.

She previously struggled with an abdominal injury during last year’s hard-court season.

Slovenian qualifier Jakupovic now faces Slovakia’s Magdalena Rybarikova in the Nature Valley Classic quarter-finals.

Rybarikova, who reached the Wimbledon semi-finals last year, overcame Kristina Mladenovic of France 3-6 6-2 6-1.

Second seed Elina Svitolina reached the last 16 in Birmingham for the first time with a 6-4 6-2 win over Alize Cornet of France.

The Ukrainian will play Romania’s Mihaela Buzarnescu on Friday, following her 4-6 6-3 6-2 win over Czech Petra Martic.

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Osaka is scheduled to play in the WTA event at Eastbourne, which begins on 25 June.

Despite the injury, she hit nine winners against Jakupovic, but the big-hitting Slovenian broke to love in the seventh game.

Osaka was unable to capitalise on two break points in the next game and she struggled to generate power on her serve, eventually retiring after 33 minutes.

“It’s never nice to win when somebody’s injured. I feel sorry for her,” Jakupovic told Eurosport.

“I was trying to focus on my play and I didn’t really look on her side, but I hope she’s going to be better for her next tournament.”

At the WTA event in Mallorca, former world number one Angelique Kerber fell 5-7 6-2 6-1 to American Alison Riske, and French top seed Caroline Garcia beat Sweden’s Johanna Larsson 6-4 6-3.

Stan Wawrinka failed to convert 12 break points as he lost to Sam Querrey in the second round of the Fever-Tree Championships at Queen’s.

The Swiss, who has dropped to 261st in the world after injury, was beaten 7-5 6-7 (3-7) 6-1 by the American.

Wawrinka, a three-time Grand Slam champion, wasted seven set points at 5-4 in the first set and only capitalised on one of 13 break points in the match.

Querrey dominated on serve, hitting 25 aces as he closed out victory.

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Fifth seed and 2010 champion Querrey will face Croatian top seed Marin Cilic, who came from behind to beat Luxembourg’s Gilles Muller 4-6 6-3 6-3.

It was a battle of the big servers as the pair delivered 36 aces between them, with Cilic edging Muller 19-17.

American Frances Tiafoe reached his first ATP grass-court quarter-final with a 6-4 2-6 6-4 win over Leonardo Mayer of Argentina.

In the ATP grass-court tournament in Halle, French Open runner-up and third seed Dominic Thiem was stunned 6-2 7-5 by world number 52 Yuichi Sugita of Japan.

Seventh seed Kei Nishikori was also knocked out, with Russia’s Karen Khachanov beating the Japanese player 6-2 6-2 to go through to the quarter-finals.

Khachanov, who reached the fourth round at this year’s French Open, will next face Roberto Bautista Agut after the Spanish fourth seed beat Dutchman Robin Haase 4-6 7-5 6-4.

The top seed in Halle is Swiss eight-time Wimbledon champion Roger Federer, who plays Frenchman Benoit Paire on Thursday for a place in the last eight.

Simona Halep has withdrawn from next week’s tournament in Eastbourne – the final grass-court event before Wimbledon – because of injury.

Romania’s world number one said she had “yet to recover” from pain and inflammation in her Achilles tendon, which began during the French Open.

Halep, 26, went on to claim her first Grand Slam title at Roland Garros.

“I’ve been advised by my doctors that it needs more rest while continuing treatment,” she said in a statement.

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Britain’s Dan Evans has not been awarded a Wimbledon wildcard because of what organisers described as a matter of “principle” after he served a ban for taking cocaine.

The former world number 41 has been in fine form since his return in April and was runner-up in the Nature Valley Open final in Nottingham on Sunday.

It means the 28-year-old must play in this week’s pre-qualifying tournament.

There were main-draw wildcards for eight Britons, including Katie Boulter.

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‘Decision based on principle’

Evans could prove difficult opposition for other players involved in pre-qualifying, having won 16 of his 21 matches since returning from his ban.

But his good form, which has lifted him to 340th in the world rankings, has not been enough to persuade Wimbledon organisers to award him a wildcard.

“This decision is based on principle in the immediacy of his return from a suspension from competition,” the All England Club said in a statement.

“He will be competing in the pre-qualifying at the All England Club this week for the opportunity to secure one of the remaining places into qualifying.”

Evans was given a wildcard for this week’s Fever-Tree Championships at Queen’s Club, where he lost in three sets to France’s Adrian Mannarino in the first round on Tuesday.

Boulter rewarded for biggest win

Boulter, who secured the biggest win of her career last week when she beat former US Open champion Sam Stosur in Nottingham, is joined by Naomi Broady, Harriet Dart, Katy Dunne, Katie Swan and Gabriella Taylor in the main draw.

Compatriots Liam Broady and Jay Clarke were given men’s main-draw wildcards, while Australian teenager Alex de Minaur – who beat Evans in the Nottingham final – also received one.

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