Injury ends Wozniacki challenge

Caroline Wozniacki retired injured midway through her second round match against Sofia Arvidsson in the Swedish Open in Bastad.

Wozniacki had taken the first set 6-2 against the home player but suffered a shoulder problem and she was forced to quit after Arvidsson had taken the first game of the second set.
It is a further blow to Wozniacki's hopes of cementing her world number one position in the build-up to the US Open. The Dane was dumped out of Wimbledon in the fourth round by Dominika Cibulkova last week.
Second seed Flavia Pennetta eased past Germany's Angelique Kerber 6-2 6-3 in 65 minutes while fourth seed Maria Jose Martinez Sanchez beat Spanish compatriot Nuria Llagostera Vives 7-5 6-1.
Fifth seed Vera Dushevina crashed out 7-6 (7/4) 6-2 6-2 to home favourite Johanna Larsson while there were also wins for Barbora Zahlavova Strycova, Polona Hercog and Vesna Dolonts.