Australian Open: Marathon man Roberto Bautista Agut into quarters after ending Cilic challenge

MELBOURNE: Roberto Bautista Agut came through a third Australian Open five-setter Sunday to knock out 2018 finalist and sixth seed Marin Cilic in the fourth round.

The in-form Spanish 22nd seed will play in his first Grand Slam quarter-final after winning 6-7 (6/8), 6-3, 6-2, 4-6, 6-4 in two minutes under four hours on Margaret Court Arena.

Bautista Agut began his season by beating Novak Djokovic en route to the Doha title and now faces Stefanos Tsitsipas for a place in the semi-finals after the young Greek star upset defending champion Roger Federer.

"I've been playing very good tennis," Bautista Agut told reporters. "I won really good matches. I had to fight so hard to stay very focussed. 

"It's been a great month for me and for my tennis."

He began his Australian Open campaign with an epic five-set win over Andy Murray, in what could be the three-time Grand Slam winner's last match because of a chronic hip injury.

His second-round match against Australian John Millman also went the full distance before a straight-sets third-round win against 10th-seeded Russian Karen Khachanov.

On Sunday he ended Croat Cilic's hopes of a repeat match-up against Federer in the quarter-finals after losing to the Swiss master in five sets in last year's final.