Murray through as Nadal's knee gives way

The fifth seeded Scot sets up a semi-final clash with Marin Cilic at the Australian Open after Rafael Nadal retires.

Rafael Nadal receives medical treatment during the third set against Andy Murray. The Spaniard was forced to retire from the Australian Open.

MELBOURNE // Andy Murray is through to the semi-finals of the Australian Open after Rafael Nadal was forced to pull out of their last-eight clash with a knee injury. An absorbing encounter was ended prematurely in the third set, although by that stage Murray had stamped his authority over the defending champion to prove a maiden grand slam success is not beyond him at Melbourne Park. The 22-year-old Scot was leading 6-3 7-6 (7-2) 3-0 when Nadal called an end to the match. It was a worrying sight for the Spaniard after the tendinitis he suffered that undermined his second half of the year. Murray will now play the Croatian Marin Cilic, who beat him in straight sets at the US Open last year, for the right to play in just his second grand slam final. There was an electric atmosphere inside the Rod Laver Arena and the match started at a hectic pace. The first key moment arrived in Murray's second service game when defending a break point both players scampered to retrieve balls before Nadal pushed a backhand volley down the line to convert his chance. Murray hit back immediately with an exquisite lob after he had failed to take two earlier break-back opportunities. The match continued at break-neck speed as Murray went 0-40 behind on his next service game before saving all three break points with serve-volley. The Scot served it out and then broke again with a confident backhand cross-court winner to allow him a chance to serve for the set at 5-3. The ebb and flow continued though as Nadal grabbed two break-back chances with a forehand which clipped the net and fell in. Murray saved them, the last with a backhand down the line, and eventually took the opener with his third set point when Nadal hit a backhand long. The players traded service games at the start of the second set before a 10-minute break was called due to the noise of a fireworks display over inner-city Melbourne to celebrate Australia Day. It failed to overshadow the cracking display on court and when the players resumed Murray was immediately broken, only for Nadal to concede the advantage straight back. The set progressed to 5-5 when yet another memorable game ensued on Nadal's service. Nadal fought off four break points and with Murray chasing down everything he could throw at him the Majorcan left-hander opted to come to the net and repel the danger with some delicate volleys. There was a worrying moment in the game, however, when Nadal slipped after a serve. Although the Spaniard indicated he was fine after the incident it was to be the moment that forced his early retirement. The tennis had been premium standard but Nadal lost the tie break 7-2 to indicate his resolve was being broken, if not by Murray's tenacity but also by his injury. The Spaniard took a five-minute medical time-out in the second game of the third set with the trainer working on his right knee. He returned but dropped the service game and when Murray held his next game the Spaniard walked up to the net and shook hands to concede the match. In a post-match interview, Murray said: "I've known Rafa since I was maybe 13 or 14 and always looked up to him. "He's my favourite player to watch because of his energy and what he brings to the court. I'm a bit gutted for him. "I came through a few tough points at the start of the match ? I had to go for them because he's the kind of player who makes you go for them. I knew I had to keep going for my shots but I played really well today." Asked for his strategy for the game, the Scot continued: "I had to go for my shots, play big tennis and when the big points came, keep them short. "I served and volleyed a little bit and it all went well. I've practised serve and volley a lot in the off-season and it went well tonight ? I might do it a little bit more often now." Cilic is Murray's next opponent and the fifth seed admitted: ""If I play like I did tonight I've got a good chance ? but the nerves will be there with it being the semi-final of a grand slam. "I lost to him in the US Open in straight sets ... he's a big guy so I'll try to keep the ball low and keep him moving."

* PA Sport