Bucharest - Third-seeded Gaels Monfils has opened his Nastase Tiriac Trophy account with a 6-1, 6-3 victory over Lithuanian qualifier Ricardas Berankis on Thursday.
Following a first-round bye, Monfils broke Berankis four times in their first meeting to reach the quarter-finals after rain delayed the start of play for more than three hours.
With Paul-Henri Mathieu or Marius Copil next, Monfils is looking to regain his early season form, when he won the title in Montpellier and reached the final in Doha.
Second-seeded Mikhail Youzhny fell in his opening match in Bucharest for a second straight year, and lost to Dutchman Robin Haase for the first time in six matches, 6-3, 6-3.
Haase faces Denis Istomin of Uzbekistan on Friday.
Results from the third day of the Bucharest ATP tournament on Thursday (x denotes seeding):
Gael Monfils (FRA x3) bt Ricardas Berankis (LTU) 6-1, 6-3
Paul-Henri Mathieu (FRA) bt Marius Copil (ROM) 6-3, 6-2
Denis Istomin (UZB) bt Adrian Ungur (ROM) 4-6, 6-0, 6-3
Robin Haase (NED) bt Mikhail Youzhny (RUS x2) 6-3, 6-3