MELBOURNE: Andy Murray stayed on track for his first Australian Open final when defending champion Rafael Nadal retired injured today, as Justine Henin’s dream run gathered pace.

The fifth seeded Scot became the first Briton since John Lloyd in 1977 to make the semi-finals in Melbourne after Nadal pulled out with a right knee problem when trailing 6-3, 7-6 (7/2), 3-0.

Murray had looked the goods during the match, pumping down 13 aces and moving around the court effortlessly as he set up a showdown with surprise package Marin Cilic. The Croatian made his first Grand Slam semi-finals by outlasting seventh seed Andy Roddick in an epic five-setter, 7-6 (7/4), 6-3, 3-6, 2-6, 6-3.

Murray, who carries an enormous burden in attempting to break Britain’s Grand Slam drought in men’s tennis stretching back to Fred Perry’s 1936 US Open triumph, said

he felt sorry for Spain’s Nadal, the second seed. “He’s my favourite player to watch just because of what he brings to the court with his energy and I’m gutted for him,” he said.

Cilic, the 14th seed, again proved his staying power, but admitted it was tough going. “It wasn’t easy. In the last set I was just trying to hold my serve, and he was putting a lot of pressure,” said Cilic, the first Croat to reach the last four in Melbourne. It was marathon man Cilic’s third five-set match of the tournament.

Roger Federer plays Nikolay Davydenko and Novak Djokovic faces

Jo-Wilfried Tsonga in the other quarter-finals on Wednesday.

Henin powered into the last four by using her vast experience to down determined Russian 19th seed Nadia Petrova 7-6 (7/3), 7-5. The 27-year-old Belgian decided to return to tennis after seeing fellow Belgian Kim Clijsters win the US Open last year, and she has more than justified the faith of organisers here who handed her a wildcard.

The draw opened up for her nicely when Clijsters was knocked out in the third round and Henin has seized the opportunity. She now faces the dangerous but unseeded Chinese Zheng Jie, who destroyed unseeded Russian Maria Kirilenko 6-1, 6-3.

Henin, whose win made her just the third women’s wildcard to reach the semi-final of any Grand Slam after Zheng at Wimbledon in 2008 and Clijsters at last year’s US Open, said she was now daring to dream. “I’m here again in the last four. It’s just much more than what I could expect and the dream continues,” said Henin, who called it quits in May 2008 after losing her enthusiasm.

Li plays Venus Williams in the other quarter-final on Wednesday, while defending champion Serena Williams takes on Victoria Azarenka of Belarus.