Nadal out of Australian Open with injured knee

Defending champion Rafael Nadal is out of the Australian Open after retiring with an injured knee during his quarterfinal against Andy Murray.

No. 5-seeded Murray became the first British man in 25 years to reach the semifinals in Australia. Murray was leading No. 2-ranked Nadal 6-3, 7-6 (2), 3-0 on Tuesday night when the Spaniard said he could not continue.

Nadal needed a medical timeout during the second game of the third set for treatment on his right knee.

Nadal struggled with knee tendinitis and was unable to defend his Wimbledon title last season after beating Roger Federer in the Australian Open final, his first major on hard courts.