World number one Rafael Nadal retired hurt in the fifth set of an enthralling quarter-final against Marin Cilic at the Australian Open.

The top seed was in visible pain on court and Cilic of Croatia will now face British number two Kyle Edmund in the semi-finals following his 3-6 6-3 6-7 (5-7) 6-2 2-0 victory.

It was only the second time in 264 Grand Slam matches that Spaniard Nadal has retired - the last being against Briton Andy Murray in the quarter-finals of the 2010 Australian Open.

Speaking following the match, Nadal said he would provide an update on his injury after an MRI scan on Wednesday.

"Now is not the moment to say what's going on or what's not going on because we really don't know yet," said Nadal.

He did, however, repeat his assertion that players are suffering injuries because of the surfaces they play on.

"Somebody who is running the tour should think little bit about what's going on," he said. "Too many people are getting injured.

"I don't know if they have to think a little bit about the health of the players. Not for now that we are playing, but there is life after tennis.

Injured Rafa Nadal

"I don't know if we keep playing in this very, very hard surfaces what's going to happen in the future with our lives."

Nadal, 31, had looked in good form early in the match and took the first set 6-3 in a typically forceful manner.

Cilic, however, was a different player in the second as he channelled his frustration at being given a time violation by breaking back at Nadal with a stunning forehand winner.

The third set was much more evenly contested and went Nadal's way in a tie-break.

Cilic was dominant on his first serve - firing down 20 aces to his opponent's three - but Nadal was able to draw the 29-year-old Croat to the net on numerous occasions - the most memorable ending in a delicate drop shot which left Cilic foundering.

Nadal's injury became apparent in the fourth set and despite lengthy delays for treatment, he was unable to continue - retiring at 2-0 in the deciding set.

"It was an unbelievable performance from both of us and it's really unfortunate for Rafa," said Cilic.

"He always gives his best and it's unfortunate for him to end this way.

"I was really paying attention to these first couple of games [in the final set] and trying to keep my intensity up. It was important for me to continue with my own game and not look across the net."