Tennis-Confident Stosur says she is back to her best

(Adds quotes, byline) By Martyn Herman PARIS, May 27 (Reuters) - Samantha Stosur said she was playing some of the best claycourt tennis of her career after beating last year's runner-up Lucie Safarova 6-3 6-7 (0) 7-5 on Friday to reach the fourth round of the French Open. The 32-year-old former U.S. Open champion reached two semi-finals and a final at Roland Garros between 2009-12 but has not made it beyond the fourth round of a grand slam since. Australian Stosur will have to defeat Romania's Simona Halep to extend her stay in Paris but was buoyant after recovering from a drubbing in the second-set tiebreak against 11th seed Safarova to claim a notable victory on Court Philippe Chatrier. "I was like, jeez, I can't remember being so happy to win in the third round," she told reporters, "It means a lot." Stosur crunched down 14 aces in a high-quality contest and broke in the last game of the match to claim only a fourth victory in 15 attempts against the Czech left-hander who defeated her in the Prague final on clay last month. Asked if she was playing as well as when she beat Serena Williams on the way to the 2010 final where she lost to Italian Francesca Schiavone, Stosur said: "Yeah, I think that's just as good as those matches. "I feel like today was a really good step up again in level. That's probably as good as I have played here for many years." Stosur must maintain that level against Halep, however, if she is to avenge a 6-2 6-0 hammering in the Madrid semi-finals this year. "I'm not going to think too much about that, why I fell apart, I'm not going to lose too much sleep over that match," she added. (Editing by Tony Jimenez)