Australian Open: Juan Martin Del Potro comes back from Karen Khachanov scare to make third round

It was only the second competitive meeting between the two, with del Potro having previously beaten the 21-year-old Russian.

Though del Potro took the first two sets, Khachanov didn't make it easy for him, losing serve only before a tie-breaker in the second set, to give the Argentinean a 6-4, 7-6 advantage.

Into the third set and del Potro was broken in the seventh set only to break right back again, and the third set was also decided by a tie-break, ending 7-0 in Khachanov's favour.

Khachanov lost his serve in the fifth game of what was to be the fourth and final set, and unable to recover del Potro won 6-4, 7-6, 6-7, 6-4.

Del Potro will play Czech Republic's Tomas Berdych in the third round.

Elsewhere in the evening session, Germany's Alexander Zverev booked a place in the third round after beating compatriot Peter Gojowczyk 6-1, 6-3, 4-6, 6-3. Zverev will play Hyeon Chung in the third round.

Fernando Verdasco was knocked out of the tournament by Maximilian Marterer after an epic three hour and thirty minute struggle ending in a 6-4, 4-6, 7-6, 3-6, 6-3 victory for the German. He will play Tennys Sandgren who shocked Stan Wawrinka with a straight set 6-2, 6-1, 6-4 vuctory.

Roger Federer set up a third round meeting with Richard Gasquet after beating world no.55 Jan-Lennard Struff 6-4, 6-4, 7-6.