Australian Open: Nadal retires against Cilic

Rafael Nadal was forced to withdraw due to a leg injury sustained during his quarterfinal match against Marin Cilic on Tuesday. This is only the second time the Spaniard has retired hurt in a Grand Slam match.

Nadal's withdrawal brought a premature end to an entertaining clash, with both players trading set wins 6-3, 3-6, 7-6, 2-6. With the Croatian up 2-0 in the fifth deciding set, Nadal called time.

Cilic, the world No. 6, will now face Kyle Edmund, ranked 49th, in the semifinals.

Edmund had continued the tournament's underdog theme earlier in the day's action, stunning third seed Grigor Dimitrov 6-4, 3-6, 6-3, 6-4. 

The 23-year-old is just the sixth British man to progress to the semifinals of a Grand Slam since tennis turned professional in 1968.

This followed a number of previous shocks in the men's draw this year, with fellow underdogs South Korean Hyeon Chung and American Tennys Sandgren having defeated Novak Djokovic and Dominic Thiem in the last 16.

And there was another upset on the women's side, as Belgium's Mertens advanced to her first Grand Slam semifinal. She defeated Ukrainian fourth seed and pre-tournament favorite Elina Svitolina 6-4, 6-0 in Rod Laver Arena.

It was the 22-year-old's first victory over a top-five player and she heads into the final four on the back of a 10-match winning streak. Mertens will now come up against second seed Carolina Wozniacki, who beat Spaniard Carla Suarez Navarro 0-6, 7-6, 6-2.

js/pfd (AP, dpa)