Injured Nadal totters out

Marin Cilic is into his second Australian Open semi-final after world No 1 Rafael Nadal retired with a leg injury during a titanic struggle on Tuesday.

Cilic, the world No 6 and former US Open champion, won 3-6, 6-3, 6-7 (5/7), 6-2, 2-0 in 3 hours and 47 minutes on Rod Laver Arena when Nadal retired in pain early in the fifth set.

He will play Britain's unseeded Kyle Edmund in an unexpected semi-final match-up on Thursday.

It was the second time Nadal has retired at the Australian Open after pulling out of his quarter-final winunbelievable Andy Murray in 2010 with a knee injury.

The Croat played in his first Australian semi-final eight years ago when he lost to Murray and it will also be his fifth Grand Slam semi-final.

Nadal was leading two sets to one before he called for the trainer and received a medical timeout trailing 1-4 in the fourth set.

He received treatment for an upper right leg injury and upon resuming his mobility was greatly affected and he lost the fourth set before calling an early end after losing a service break at 0-2 in the fifth.

"It was an unbelievable performance from the both of us and it is really unfortunate for Rafa, he's an unbelievable competitor, always gives his best and it's very unfortunate to finish this way for him," Cilic said. "When you are wounded, sometimes the balls are going in, you are a little bit looser, so I was really paying attention to these first couple of games, just try to keep my intensity up.

"Overall I had a lot of chances there to break and somehow just Rafa was coming with some good serves, good shots in critical moments.

"That's the way he has always been, always finding the way, even if he is not playing at his best level."

Edmund upsets Dimitrov

Kyle Edmund became only the sixth British man to reach a Grand Slam semi-final with an upset win over world No 3 Grigor Dimitrov at the Australian Open on Tuesday.

The unseeded Edmund, ranked 49, won 6-4, 3-6, 6-3, 6-4 in 2hr 49min on Rod Laver Arena and will face either 16-time Grand Slam champion Rafael Nadal or Marin Cilic for a place in the final.

With another British Grand Slam semi-finalist Tim Henman watching on in the stands, 23-year-old Edmund troubled Dimitrov with his powerful forehand and serve.

"It's an amazing feeling, very happy with these sort of things, you are so emotionally engaged that you don't really take it in, you don't really enjoy yourself," Edmund said.

"It was my first match on Rod Laver Arena and it is very special."

Edmund is the only British man in this year's field after five-time finalist Andy Murray's injury withdrawal before the tournament.

Wozniacki, elise advance to semis

Caroline Wozniacki has advanced to the semifinals at Melbourne Park with a 6-0, 6-7 (3), 6-2 win over Carla Suarez Navarro in an early Wednesday morning finish at Rod Laver Arena.

The second-seeded Wozniacki won the first seven games of the match but trailed 4-2 in the second set before staging a comeback. Suarez Navarro had to save one match point in the 10th game before Wozniacki was outclassed in the tiebreaker.

Wozniacki had an early break in the deciding set to take a 4-2 lead, then broke again in the seventh game before serving out the match in 2 hours, 11 minutes.

Wozniacki, who can return to the No 1 ranking with her first Grand Slam singles title, plays Elise Mertens in the semifinals. Mertens has taken a 10-match winning streak straight into the Australian Open semifinals.

The 22-year-old Belgian player had an upset 6-4, 6-0 win over No 4 Elina Svitolina in the first women's quarterfinal on Tuesday at Rod Laver Arena.

Mertens, ranked 37th, successfully defended her Hobart International title two weeks ago, and has now won five matches at Melbourne Park.