ROTTERDAM, Netherlands (AP) Second-seeded Marin Cilic reached the World Tennis Tournament quarterfinals by defeating Gilles Muller of Luxembourg 7-6 (2), 7-6 (7) in the second round on Wednesday.
Neither player faced a break point in the first set, but Muller saved five in the second.
Cilic had two match points at 6-4 in the tiebreak, then saved a set point at 7-6 down as Muller fought back strongly.
''I was expecting a close match. Luckily, I was serving well and I was mentally focused,'' said Cilic, runner-up here to Tomas Berdych two years ago. ''Gilles is a very difficult player to play against indoors, and I'm happy to be through.''
The 2014 U.S. Open champion next plays Philipp Kohlschreiber, who won against qualifier Ivan Dodig of Croatia 6-4, 6-2.
The German proved clinical on Dodig's serve, converting four of five break-point chances, and solid on his own - winning 75 percent of points on second serve.
Meanwhile, fifth-seeded Gael Monfils of France beat 19-year-old Borna Coric of Croatia 6-3, 5-7, 6-2 in a match littered with 22 break-point chances.
Monfils served for the match at 5-4 in the second set then lost three straight games.
He finally served out victory to set up a match against either countryman Gilles Simon, seeded third, or German teenager Alexander Zverev - who won their first-round matches on Wednesday.
In other first-round play, No. 8-seeded Viktor Troicki, Jeremy Chardy, and Roberto Bautista Agut also advanced.