Grigor Dimitrov's hot run of form shows no sign of abating after he cruised into the Rotterdam Open quarter-finals with a straight-sets victory over Denis Istomin.

The fifth seed survived a first-set scare against Mischa Zverev to reach round two and, after battling to victory in the opener, he stepped up a gear to come away with a 7-6 (9-7) 6-1 victory.

Dimitrov's 2017 record now stands at 16-1 and David Goffin - the man he beat on home soil to win the Sofia Open last week - awaits him in the last eight.

Belgian third seed Goffin came from a set down to beat home hope Robin Haase 5-7 6-4 6-4. The duo were tied in the decider until 4-4, when Goffin fired over two backhand winners to take control.

Top seed Marin Cilic saw off fellow Croatian Borna Coric 6-1 2-6 6-4, winning the first five games before his opponent recovered to make a contest of the match.

But Coric failed to capitalise on five game points at 3-3 in the final set, opening the door for Cilic to pounce on his profligacy and make the decisive break.

Cilic faces Jo-Wilfried Tsonga in the quarter-finals, while Tomas Berdych's victory over Richard Gasquet sets up a clash with Martin Klizan.

Second seed Dominic Thiem beat Gilles Simon 6-4 7-6 (7-4) in the final match of the day and will meet Pierre-Hugues Herbert next.