MASON, Ohio (AP) --
Marat Safin barely moved while the match-ending ace flew by, then tossed his racket onto the court in exasperation. The U.S. Open is at hand, and the Australian Open champ is in a bad way.
Wild card entry Robby Ginepri needed only 56 minutes Friday to knock Safin out of the $2.45 million Cincinnati Masters. Ginepri advanced to the semifinals with a 6-2, 6-3 victory over the hobbled Russian.
Top-ranked Roger Federer also reached the semifinals with a 6-4, 6-3 victory over Jose Acasuso. The rest of the field would be set after evening matches.
Safin was seeded fourth in Cincinnati, but hadn't played since Wimbledon because of a slightly torn ligament in the left knee. He hadn't even practiced much, hoping rest and treatment would get the knee strong enough for the Open.
It hasn't gone that way.
Safin complained throughout the tournament that the knee still hurt, making him tentative on the court. There were several times Friday when he came up awkwardly after planting on the knee, which was protected by a wrap.
He said the knee felt a little more inflamed on Friday during his third match of the week.
"I didn't practice for one month and a half and I played three matches in a row and today I felt really, really tired on the court,'' said Safin, his knee covered by a bulky ice bag after the match. "I couldn't move properly and I couldn't find my game. My timing was not there. So it's really difficult to play against any player.''
Safin's doctors told him there's a chance he could make the injury worse by playing competitively, but he has decided to play in the U.S. Open rather than take off for a longer time. He'll rest next week and hope he's got enough to handle the five-set format at Flushing Meadows with a bum knee and a rusty game.
"I don't think it's really enough, but it's the best I could manage,'' he said.
At less than full strength, he had little chance against Ginepri, who has a 14-2 record on hard courts this summer. Ginepri pulled ahead 3-0 in the first set and kept Safin on the move, giving him no opening to rally.
Safin never put much pressure on Ginepri, who had only three unforced errors in the match and never faced a break point. When he got up 3-0 in the first set, Ginepri was confident he could handle him.
"You never know what to expect with Marat,'' Ginepri said. "He can be on fire every shot and blow you off the court 6-0, 6-1, so you've just got to be on your toes.''
Federer also took off after winning his third straight Wimbledon, in part to relax and in part to let a sore foot heal. Federer has done a much better job than Safin at getting healthy and getting back in the flow.
Federer has been ranked No. 1 for the last 81 weeks -- the seventh-longest stay atop the ATP rankings -- and appears to be back in form in time for the U.S. Open. He's 36-1 on hard courts this year and seems refreshed after his extended summer layoff.
He needed only 63 minutes to win in the quarterfinals Thursday, and took control against Acasuso by pulling ahead 3-0 in the first set. Federer has gotten a little sharper each day of the tournament.
"My confidence is back,'' he said. "You lose it when you don't play. I've earned it again. That's the thing I've achieved this week.''