NEW YORK (AP) – Rafael Nadal felt a pain in his right knee early in his semifinal at the US Open, in what he called "a bad move." It was a familiar pain, one with which he has struggled intermittently for years.
The defending champion looked up at his guest square and indicated that something was wrong. He tried to continue. Finally, he could not.
Nadal stopped playing after losing the first two sets on Friday night, putting Juan Martin del Potro in the Grand Slam final for the first time since winning the 2009 title at Flushing Meadows.
"It was not a tennis match at the end, only one player played, the other was on the side of the court," said Nadal. "I hate to retire, but staying one more there, playing like that, would be too much for me."
Del Potro led 7-6 (3), 6-2 after two hours of play when Nadal shook his head and said he had to stop.
"Of course, it's not the best way to win a game," said Del Potro, who hugged Nadal when he finished. "I do not like to see him suffer on the court today, so I'm sad for him."
Nadal, number one, has a history of tendonitis in his knees, and is often cited when he retires from tournaments. He was visited by a coach in the change after the seventh game of the match and the tape was applied under the joint.
In the next change, however, Nadal took out the tape.
After the third game of the second set, he had a doctor time out so the coach could massage his right leg and re-apply the tape.
But the movement of Nadal was clearly limited and in the end he walked with a small problem in his walk between points. At one point, he approached the chair umpire to complain about a late call from a line judge and mentioned in passing that he was going to have to resign. Very soon, he did exactly that.
Nadal said he did not know what kind of effects might have persisted in his quarter-final win over Dominic Thiem, which lasted five sets and nearly five hours. But he had a knee problem at the beginning of the tournament, when he did record during his victory against Karen Khachanov in the third round.
For Del Potro, it was a strange way to return to an important summit. Nine years ago, he surprised Nadal in the semifinals, then Roger Federer in the final, to win the US Open at age 20. He was considered a rising star at that time, but a series of wrist operations, one on his dominant right arm, and three on his left – slowed his career and kept him out of tournaments older than 2½ years.