Lukas Rosol made a successful start to his defence of the Nastase Tiriac Trophy in Bucharest after a straight sets victory against Filippo Volandri on Tuesday.
The big-serving Czech will face Finnish eighth seed Jarkko Nieminen in the second round after seeing off Italian world No 83 6-1 7-6 (8/6).
Dutchman Robin Haase beat Matthew Ebden 6-4 6-3 to set up a date with second seed Mikhail Youzhny, while Ricardas Berankis lies in wait for third seed Gael Monfils after coming through an all-qualifier battle with Nikoloz Basilashvili 6-7 (2/7) 6-3 6-4.
Home favourite Victor Hanescu, a 6-3 6-4 winner against Dudi Sela, will provide the opposition for fourth-seeded Gilles Simon.
Qualifier Adrian Ungur followed Hanescu in the next round after dispatching fifth seed Vasek Pospisil 5-7 6-2 6-1, while his Romanian compatriot Marius Copil upset Adrian Mannarino 6-1 6-4.
Carlos Berlocq from Argentina beat sixth seed Andreas Seppi 6-0 2-6 7-6 (7/4) and in the all-French battle Paul-Henri Mathieu strolled past Nicolas Mahut 6-3 6-1.