How Andy Murray defeated Rafael Nadal in the Australian Open

Andy Murray is through to the Australian Open semi-final after Rafael Nadal retired through injury.

The British No 1 won the first two sets 6-3, 7-6 and was 3-0 up in the third when the defending champion conceded the match.

Nadal had taken time out during the previous game to have treatment on his right knee. The world No 2 has been troubled by tendonitis in his knees for the past twelve months, an injury which forced him to relinquish the defence of his Wimbledon crown last season.

Murray will play Marin Cilic in the last four after the Croatian defeated Andy Roddick in five sets earlier today.

Nadal retires: Murray wins

And that's a sad end to the match. Nadal goes over to Murray, puts his hand on his shoulder and concedes the match.

Murray 3-0 Nadal

As Murray goes cross-court to Nadal's forehand, the Spaniard gives up the chase and shakes his head. His knee must still be troubling him. A terrific cross-court pass of his own brings Nadal back to 15-all but Murray's next serve produces yet another ace. Nadal pushes Murray onto the back foot with a couple of his traditional blasts and he forces a break point of his own as Murray uncharacteristically dumps one into the net. Big serve. Ace. Deuce. Murray is coming up with the goods when he needs them most. And then he snaps a string. That's advantage Nadal.Take that! Murray fires down another ace. And another one gives him the advantage. Nadal is slow to get to a pass, Murray ties up the game.

Murray 2-0 Nadal

Nadal's off his chair and trotting back onto the court. His face spells worry and doubt. We continue at 15-all. Nadal's movement looks ok during the first rally back, but he still nets a backhand. A cross-court backhand from Murray clips the top of the net and is called out. Murray challenges - it's in. The point is replayed for some reason before Murray rips one down the line to earn two break points. He only needs one as he steams ahead in the third set.