Second seed Cilic, a 2014 finalist at the Ahoy stadium, left Denis Istomin without a win at the event for a third straight year, posting a 7-6 (7/5), 6-4 victory.

The 2014 US Open winner hopes to take his progress one step further after his best here two years ago when he finished runner-up to Tomas Berdych,.

"To win here would be a huge honour. but the tournament is tough," he said.

"I can only go step by step, there is no other way. But I will be pushing myself hard to try and win it."

Cilic spent just over 90 minutes in firing 10 aces and breaking once from seven chances against the Uzbek coached by his mother. The seed never faced a break point.

"It was a tough, mental challenge," the 13th-ranked winner said. "The first set was very close and the second was a mental battle.
"I was lucky to pull it through."

Dodig, the world number 87, was coming off a first-round loss to a wild card at the Australian Open.

But the Croatian whipped his game into shape during Rotterdam weekend qualifying and put his form to good use with a 6-3, 7-6 (7/4) defeat of seventh-seeded Benoit Paire.

Paire, one of seven French players in the draw, committed well over 50 unforced errors in what was a frustrating effort.

It required 90 minutes for Dodig to take revenge for a 2013 loss in Monte Carlo to the Frenchman.

Paire, who has now lost his last four matches dating to mid-January, saved a match point in the tenth game of the second set and made Dodig, ranked 87th, work for the victory. The Croatian advanced on his third chance from a concluding Paire error.

Jiri Vesely won an all-Czech battle in the first round as he defeated Lukas Rosol 6-4, 6-2.

France's Richard Gasquet takes the top seeding in the event which lost Roger Federer at short notice last week to minor knee surgery.

Gasquet comes to the Netherlands with a 13th career title to hand after winning in Montpellier at the weekend.