Nadal retires at U.S. Open, del Potro advances

Defending champion Rafael Nadal retired from his U.S. Open semifinal because of a painful right knee after dropping the opening two sets, putting Juan Martin del Potro back in a Grand Slam final for the first time since he won the 2009 title at Flushing Meadows.

Del Potro was leading, 7-6 (3), 6-2, after two hours of play Friday when Nadal shook his head and said he had to stop.

“That was not a tennis match at the end. Just one player playing, the other staying on one side of the court,” Nadal said. “I hate to retire, but staying one more set out there, playing like this, would be too much for me.”

The No. 1-seeded Nadal has a history of tendinitis in his knees and he said he felt a problem in the right one early in the first set. He was visited by a trainer at the changeover after the match’s seventh game and tape was applied below the joint.

Golf

SCHAUFFELE IN FRONT AT BMW CHAMPIONSHIP» Ryder Cup captain Jim Furyk had an easy time deciding on three of his four picks for the Ryder Cup.

Xander Schauffele is making the last one a little more difficult.

Schauffele nearly holed a wedge on his second hole, rolled in a 40-foot birdie putt in the middle of his round Friday and wound up with a 6-under 64 in the BMW Championship for the lowest 36-hole score of his career and a two-shot lead over Justin Rose.

“I’m sort of in a position where I feel like a win is the only way I’d even be in consideration,” Schauffele said.

He also made it more difficult on Woods, who again goes into a weekend have to catch up to the leaders.