Del Potro into US Open final as Nadal retires
Juan Martin del Potro will compete in his first Grand Slam final for nine years after defending champion Rafael Nadal retired from their US Open semi-final.
Argentine third seed Del Potro was leading 7-6 (7-3) 6-2 when Nadal quit because of a knee problem.
Top seed Nadal, 32, twice needed medical attention before conceding.
“It was difficult for me to keep playing. I was in too much pain and it was not a tennis match,” said Nadal.
“It was one player playing and one on the other side of the court.
“I hate retiring but to stay one more set out there playing like that is too much for me.”
Del Potro, the 2009 champion, will face Serbia’s Novak Djokovic in Sunday’s final after the 13-time Grand Slam winner beat Japan’s Kei Nishikori in straight sets.