Yanina Wickmayer was forced to retire from her first round match at the Texas Tennis Open in Dallas. Elsewhere, Andy Murray says he'll compete at the Thailand Open next month.
Tennis round-up: Wickmayer withdraws in Dallas
Yanina Wickmayer, the fourth seed, was forced to retire during her match against Sofia Arvidsson in the first round of the Texas Tennis Open in Dallas.
The Belgian had won the first set 6-4 before the Swede romped to a 6-0 second set success.
Arvidsson was 1-0 up in the deciding set when her opponent withdrew, putting her in doubt of the US Open, which is less than a week away.
The second-seeded Dominika Cibulkova had no such problems, disposing of Mirjana Lucic 6-4, 6-0.
Shahar Peer enjoyed a 6-1, 6-3 win over Anastasiya Yakimova, and Melanie Oudin was the beneficiary of the retirement of Akgul Amanmuradova.
Kateryna Bondarenko defeated Greta Arn 6-2, 6-3, and Elena Baltacha beat Barbara Zahlavova Stycova 6-2, 6-1.
Angelique Kerber prevailed after almost two hours 20 minutes to beat Chanelle Scheepers 4-6, 6-2, 7-5.
Elsewhere, Andy Murray, the world No 4, is set to compete at the Thailand Open next month, along with a clutch of rising stars, organisers said.
Murray, who defeated the world No 1 Novak Djokovic to win the Western & Southern Open in Cincinnati last week, was runner-up at the Thai tournament in 2005.
He will join two past Thailand Open champions - Gilles Simon and Guillermo Garcia-Lopez - at the September 24 to October 2 event, which will use the Hawk-Eye electronic ball tracker for the first time.
"More and more world-class tennis players are joining our tournament. The technology, too, will make our tournament world class," said Suwat Liptapanlop, the Thailand Open executive committee chairman, at a news conference.
Last year Garcia-Lopez, now ranked 37 in the world, beat Jarkko Nieminen 6-4, 3-6, 6-4 in the final to win his second ATP Tour title.