Karlovic hits back to win in Antwerp

The Croatian, now 38 and an eight-time winner on tour, defeated Guido Pella 3-6 7-5 7-6 (12/10).

Belgian hope Ruben Bemelmans was also taken to three sets as he edged Peter Gojowczyk 4-6 7-6 (7/5) 7-6 (7/2) over almost two-and-a-half hours.

At the other end of the scale Frenchman Julien Benneateau was on court less than an hour before opponent Nikoloz Basilashvili retired through injury after losing the first set.

Serghey Stakhovsky also progressed, beating Jared Donaldson in straight sets.

In Moscow's Kremlin Cup Israel's Dudi Sela came through with a straight sets over Borna Coric in the first round.

Sela is ranked 72 in the world, 16 places below his opponent, but won 6-3 6-2.

Elsewhere Alexander Bublik eased past Teymuraz Gabashvili 6-3 6-4 and Indian qualifier Yuki Bhambri defeated Roman Paviullin 6-2 6-4.