Rafael Nadal, Marin Cilic
Tennis - Australian Open - Quarterfinals - Rod Laver Arena, Melbourne, Australia, January 23, 2018. Rafael Nadal of Spain leaves after retiring injured in his match against Marin Cilic of Croatia. Reuters / Thomas Peter

World No. 1 Rafael Nadal retired hurt Tuesday from his quarter-final match against World No. 6 Marin Cilic at the Rod Laver Arena. Nadal, in pursuit of his second title at Melbourne Park, was trailing the fifth set 0-2 when he decided to forfeit the match and end his 2018 Australian Open campaign.

Cilic dominated Nadal through most of his 3-6, 6-3, 6-7 (5-7), 6-2, 2-0 victory. The Croatian hit twice the amount of winners as Nadal and put forward a service game clinic to reach his career fifth Grand Slam semi-final.

2018 Australian Open: Rafael Nadal battles through injury

After the victory, Cilic sympathised with Nadal and praised the Spaniard for fighting through injury. "Unbelievable performance from both of us and really unfortunate for Rafa. He’s an unbelievable competitor and it’s really unfortunate for him to finish this way. As often happens when you’re wounded, sometimes you’re a little bit looser. So I was really paying attention in this first couple of games, trying to keep my intensity up.

"He was struggling to return my serve, especially the slider out wide. I was using it a lot and it was working most of the time. The tie break was weird. I made a few errors. In the third set I had a lot of chances and somehow Rafa was coming up with good shots at critical moments and that’s the way he’s always been, finding the shots even when he’s not at his best level," Cilic told Jim Courier in his post-match interview, via The Guardian.

Marin Cilic, the 2014 US Open champion, will now face unseeded Briton Kyle Edmund in Thursday's semi-final. "Kyle Edmund has had an amazing run in the tournament. A few five setters, great battles, and big congratulations for him. I have to keep going with my own game. Kyle is also a big hitter. I have to take things in my own hands," Cilic said about his opponent.

The other semi-final will pit either defending champion Roger Federer or Czech veteran Tomas Berdych against either Hyeon Chung or American Tennys Sandgren. With Nadal, Grigor Dimitrov and Novak Djokovic out of the tournament, Federer is the overwhelming favourite to win Grand Slam title No. 20 on Sunday. The 2018 Australian Open continues Wednesday with the next set of quarter-finals matches.