Melbourne, Jan 26 (DPA) Andy Murray advanced to a first semi-final at the Australian Open as defending champion Rafael Nadal quit while trailing 6-3, 7-6(2), 3-0 with a knee pain Tuesday.
The problem which prevented the Spaniard from defending his Wimbledon title last year flared again, with Nadal retiring after two and a half hours to hand Murray victory.

The Scot next faces Croatian Marin Cilic, who struggled through a five-set marathon to bury Andy Roddick - bothered by a shoulder problem - 7-6 (4), 6-3, 3-6, 2-6, 6-3.

Murray always looked in control against Nadal, whose fitness has been a suspect for more than six months due to his knee problem, that resulted in his loss at Roland Garros in the spring after winning four straight titles.

Murray lifted the first set in nearly an hour, took the second on a tie-breaker and coasted in the third as Nadal was unable to go on after playing and losing the three games.

It marked only the third win for Murray against seven losses to Nadal.

The contest ended suddenly as Nadal stopped, unable to continue due to his chronic problem and was forced to receive the treatment after the first game of the third set.

Murray has so far not lost a set.

Cilic’s victory on a national holiday was hard-fought, with Roddick looking like packing it in after being treated for the shoulder pain.

“It wasn’t easy,” said the relieved 14th seeded Croatian. “But I had experience - it was his third five-set match of the tournament - during the week.

“In the fifth set I had a few extra gears. He started to play better and I struggled on serve.

“He was putting the pressure on and I didn’t know what to do. But point by point, starting win the first game when I held from 0-40 down, I managed.”

Roddick rallied from the depths to hang on and make a match of it against Cilic.

“By the end of the first set, I was pretty numb in the bottom two fingers,” said Roddick. “I could still hit it pretty hard; I was just having trouble controlling it.

“That was unfortunate. I hit the ball about as well as I could.”

Cilic grabbed a 4-1 lead in the final set but had to hold on as seventh seed Roddick made a massive survival bid before finally going down. The American fired a return wide at the net to lost in just under four hours.

“In the fifth, I was always going to need a break or two with the way I was kind of chunking my serve around,” admitted the American.

The Croatian produced 19 aces against 13 for the hampered Roddick, with Cilic breaking five times and finding 81 winners.

The American four-time semi-finalist is already dealing with a knee problem last autumn which forced him to end his 2009 in October.

Roddick took a medical timeout after losing the opening set in a tiebreaker, telling the trainer he felt sharp pain in his right shoulder on big serves and high forehands.

On the women’s side, Justine Henin moved closer to regaining her place at the top of tennis as the currently unseeded seven-time Grand Slam champion reached the semi-finals over Nadia Petrova 7-6(3), 7-5.

Henin is competing in only her second event since her return and is lined up for a semi-final against China’s Zheng Jie, who beat Russian Maria Kirilenko 6-1, 6-3.

“Today was my first match in the sun actually since I was in Australia,” said Henin, 27. “We were playing under the roof in Brisbane.”

“Here I’ve played almost every match in night session. And it was quite cloudy the other day when I played in the day. It was really difficult to find a good rhythm.”

Jie is to play for the second time in a Grand Slam semi-final after reaching that stage at Wimbledon in 2008.

“For me, this is amazing,” world number 35 Jie said . “It was a tough match because she beat Maria Sharapova in the first round.”

Henin, who retired as world number one in 2008 but made a return to the sport at the start of January, showed that she has lost little of the form which took her to the top of the game before her sudden retirement.