Serena Williams has yet to find anyone who can push her for two sets or beat her in one at this year's U.S Open. Next to give it a try: none other than the top-ranked player in the world, Caroline Wozniacki. Williams and Wozniacki each won in straight sets Thursday to set up a semifinal meeting at Flushing Meadows in the headliners' half of the draw. Williams defeated No. 17 Anastasia Pavlyuchenkova, 7-5, 6-1 and Wozniacki beat No. 10 Andrea Petkovic 6-1, 7-6 (5). Read more: http://espn.go.com/tennis/usopen11/...ha-stosur-angelique-kerber-advance-semifinals