Sixth-seeded Andreas Seppi was knocked out of the first round of the Nastase Tiriac Trophy on Tuesday, along with seventh-seeded Nicolas Mahut.
Carlos Berlocq of Argentina ousted Italy's Seppi 6-0, 2-6, 7-6 (4) on the outdoor clay at the BNR Arenas, while qualifier Paul-Henri Mathieu defeated Mahut 6-3, 6-1 in all-French contest.
Defending champion Lukas Rosol made a winning start, beating Italian Filippo Volandri 6-1, 7-6 (6).
Romanian hope Victor Hanescu defeated Israel's Dudi Sela, 6-3, 6-4 and wild card entrant Marius Copil of Romania downed Frenchman Adrian Mannarino 6-1, 6-4 in a match lasting just over one hour.
In other matches, Denis Istomin of Uzbekistan ousted Brazil's Thomaz Bellucci 7-6 (6), 7-6 (6) and Robin Haase of the Netherlands beat Australia's Matthew Ebden 6-4, 6-3.