Marin Cilic survived a tough examination by Canadian Vasek Pospisil to reach the Miami Open fourth round.

The second seed prevailed 7-5 7-6 (7-4) after nearly two hours on court.

The big-hitting Cilic fired six aces and saved all three break points he faced, but the 77th-ranked Pospisil made it more difficult than the Croat probably expected.

Trailing 5-6 0-40 in the second set, the Canadian saved three consecutive match points and hit a running forehand pass to cap a 33-shot rally before Cilic claimed victory in the tiebreak.

With Swiss top seed Roger Federer knocked out in the second round by Australian Thanasi Kokkinakis, Cilic will be eyeing his first title of the year and 18th of his career.

Indian Wells champion Juan Martin del Potro thumped Kei Nishikori 6-2 6-2.

The fifth-seeded Argentine was far too good for the error ridden Japanese 26th seed taking just 72 minutes to wrap up the match.

Del Potro will meet Filip Krajinovic in the round of 16 after the Serbian 22nd seed defeated Frenchman Benoit Paire 6-3 6-3.

South Korean Chung Hyeon, the 19th seed, needed just 62 minutes to dispatch American qualifier Michael Mmoh 6-1 6-1, winning 84 per cent of his first serve points.

Asia’s highest-ranked player will next face Portugal’s Joao Sousa, who outlasted American Jared Donaldson 1-6 6-3 6-4.