Sharapova left with no answer as Wozniacki keeps No 1 spot in her sights

The current US Open was reckoned to be Maria Sharapova's best chance of winning a Grand Slam title since she claimed her third major crown in Melbourne two and a half years ago, but the 23-year-old Russian was outplayed here last night by the form player of women's tennis.

Caroline Wozniacki, the runner-up 12 months ago, has lost only one of her 20 matches since Wimbledon and added Sharapova to her victims with a display of great athleticism and consistency. The 20-year-old Dane, who won 6-3, 6-4, kept making Sharapova hit the extra ball, forcing the Russian into 36 unforced errors, 26 more than her opponent.

Nevertheless, it was a hard-fought win, the match lasting an hour and 53 minutes. Sharapova dominated many of the rallies with her bigger ground strokes but failed to take her chances, converting only one of nine break points. The Russian has never served as effectively since her shoulder operation two years ago and nine more double faults here contributed to her downfall.

Wozniacki, who will become world No 1 if she wins the title on Saturday, next plays Slovakia's Dominika Cibulkova, who knocked out Svetlana Kuznetsova, the 2004 champion and 2007 runner-up. Cibulkova, who won 7-5, 7-6, is the world No 45 and the lowest ranked player left in the women's draw.

It was a bad 24 hours for Russian women. The night before, Elena Dementieva was beaten 6-3, 2-6, 7-6 by Samantha Stosur in the best contest of the women's tournament to date, the Australian saving four match points. The fourth-round match, which lasted two hours and 38 minutes, ended at 1.35am, the latest finish to a women's match in the history of the tournament.

Sam Querrey is the last American left in the men's singles after Mardy Fish went down 6-3, 6-4, 6-1 to Novak Djokovic yesterday, John Isner having lost to Mikhail Youzhny the previous night. Djokovic, who has reached the semi-finals or better in his last three appearances here, losing to Roger Federer on each occasion, now faces Gaël Monfils in the quarter-finals.

Laura Robson, who lost in the final round of qualifying for the senior competition, began her quest for the junior title with a comfortable 6-2, 6-1 victory over Slovakia's Anna Karolina Schmiedlova. She next plays the American Chanelle Van Nguyen. George Morgan, the other British junior in action, beat Ecuador's Roberto Quiroz 6-4, 4-6, 7-5 and now faces Slovakia's Filip Horansky.