Tsonga to miss U.S. Open due to knee injury

PARIS, Aug. 15 (UPI) -- Jo-Wilfried Tsonga, ranked eighth in the world, announced Thursday he will miss the U.S. Open due to an ongoing knee problem.

Tsonga hasn't appeared at an ATP event since retiring from a second-round match at Wimbledon because of a left knee injury.

He reached the semifinals of the French Open in June and has a 30-11 match record this year. He defeated sixth-ranked Tomas Berdych in the finals of the ATP tournament in Marseille in February for his 10th career title.

Three of his loses have come in tournament semifinals.

Tsonga said on his website he expected to return to the court in September.

The U.S. Open, the year's final tennis major, is to begin Aug. 26 in New York.