Little separated Nadal and big-hitting Cilic until the injury struck, as they traded ferocious groundstrokes in an intense battle. But the Spaniard, who was beaten in last year's final by Roger Federer, called the physio at 1-4 in the fourth set and again at the changeover when two sets apiece and the writing was on the wall. "It was an unbelievable performance from both us," said Croat Cilic, the sixth seed. "It is really unfortunate for Rafa to finish this way." Nadal's retirement follows the departure on Monday of Novak Djokovic, with his immediate playing future uncertain after an elbow injury flared. He also appeared to have a hip problem."Really unfortunate for Rafa. He is an unbelievable competitor. Always gives his best and it's very unfortunate for him to finish this way. " - @Cilic_Marin will play @Kyle8Edmund in the SF. Kudos to the ?? on a superb performance nonetheless. #AusOpen pic.twitter.com/rMFIW9Wl4a
— #AusOpen (@AustralianOpen) January 23, 2018
There were no such troubles for Edmund against Dimitrov, as he became only the fourth British man to reach the Australian Open semi-finals in the post-1968 Open Era. "It's an amazing feeling. I'm very happy," said the overwhelmed 23-year-old, ranked 49. "It was a hard match and I'm really trying to enjoy the moment. It was my first match on Rod Laver Arena and it's very special."Unfortunate scenes here with the world No.1 Rafael #Nadal retiring hurt in the QF ?@Cilic_Marin progresses through to the SF. #AusOpen pic.twitter.com/IEjPruzvdi
— #AusOpen (@AustralianOpen) January 23, 2018
He is the only British man in the draw after Andy Murray's injury withdrawal before the tournament, raising the prospect that it will be him, rather than the Scot, who breaks through to win in Australia. Murray has been a five-time finalist, but lost them all.BREAKING: Kyle Edmund through to Australian Open semi-finals after 6-4 3-6 6-3 6-4 win over Grigor Dimitrov. #SSN pic.twitter.com/T5Kzbe3z5J
— Sky Sports News (@SkySportsNews) January 23, 2018


