Top seed Rafael Nadal needed four sets to beat Argentina’s Diego Schwartzman on Sunday and reach the quarter-finals of the Australian Open.

Nadal had to work hard for his 6-3, 6-7 (4-7), 6-3, 6-3 win. The Spaniard’s serve was broken three times in the second set, which the diminutive Schwartzman went on to win after a tiebreak.

But the world No 1 raised his defensive game to take the next two sets and set up a semi-final clash with Croatian Marin Cilic, who beat 10th seed Pablo Carreno Busta 6-7 (7-2), 6-3, 7-6 (7-0), 7-6 (7-3).

‘It was a great battle. He is a good friend of mine,’ said Nadal of Schwartzman. ‘He is a great player, in all aspects, and I feel that for a lot of moments he was serving well.

‘I was able to keep fighting until the end and it is the first big match I have played in 2018. It probably helps my confidence, knowing I can resist almost four hours on court.’

In other fourth-round matches, Bulgaria’s world No 3 Grigor Dimitrov knocked out big Australian hope Nick Kyrgios with a 7-6, (7-3), 7-6 (7-4), 4-6, 7-6 (7-4) win.

‘Playing against Nick is always tricky, two weeks ago I lost against him,’ Dimitrov said.

‘He was serving and playing unbelievable and he fought really hard. It’s one of those matches that you have to be locked in and try to get any opportunity you have.

‘Even when I was serving for the match I felt that I was not finding my spots very well and I’m just glad I got through that match.’

Dimitrov will next face Britain’s Kyle Edmund, who reached the quarter-finals of a Grand Slam for the first time after coming from a set down to oust Italian Andreas Seppi 6-7 (4-7), 7-5, 6-2, 6-3.