Marin Cilic booked his place in the Rotterdam Open second round with a 7-6 (7-5) 6-4 victory over Denis Istomin on Monday.
A runner-up in 2014, Cilic hit 10 aces and won 90 per cent of his first service points in a closely fought encounter that did not see a break point until the final game.
Cilic needed an hour, 36 minutes as the second seed awaits either Andreas Seppi or Gilles Muller in the last 16 of the ATP 250 event.
"It was a very close match," said Cilic. "Denis is the kind of player that can play really, really well, especially indoors. He's got really good shots from the back of the court.
"I think it was a strange match today. Both of us were serving extremely well. There were no breaks of serve in the match until the last game.
"I was threatening a lot in the second set and was close to converting some break opportunities. I had to hang in there mentally. I was moving well and serving well and that was key for me."
Seventh seed Benoit Paire became the first big casualty of the tournament as he lost 6-3 7-6 (7-4) to Croatian qualifier Ivan Dodig, while Jiri Vesely saw off Lukas Rosol 6-4 6-2.
In the day's remaining ties, Borna Coric triumphed 7-6 (11-9) 4-6 6-3 over Thiemo de Bakker, who squandered a remarkable 10 set points in the opener.
Nicolas Mahut, meanwhile, defeated Teymuraz Gabashvili 6-4 7-6 (7-4).