Nadal withdraws from Miami semi with knee injury

KEY BISCAYNE, Fla. (AP)â€"Rafael Nadal has withdrawn two hours before the start of his semifinal Friday at the Sony Ericsson Open because of a left knee injury that has bothered him in recent matches.

With his withdrawal, 2009 champion Andy Murray advanced to Sunday’s final. He’ll play the winner of Friday night’s match between top-ranked Novak Djokovic and No. 21-seeded Juan Monaco.

Nadal has had knee problems in recent years, and his left knee has bothered him since Indian Wells. He lost there to Roger Federer in the semifinals two weeks ago.

Nadal took a medical timeout for treatment of his knee during a fourth-round victory at Key Biscayne and said afterward he was in less-than-perfect health. The 10-time Grand Slam champion had hoped to claim his first Key Biscayne title.