Top seed Janko Tipsarevic eased into the quarterfinals at the $535,000 Nastase Tiriac Trophy tennis event.
The world No. 10 from Serbia blew past Colombian Santiago Giraldo 6-3, 6-3 on the red clay at BNR Arenas. Tipsarevic will face Spaniard Guillermo Garcia- Lopez in Friday's quarters.
Meanwhile, heavy Romanian crowd favorite Victor Hanescu upset fourth-seeded Russian Mikhail Youzhny 6-4, 6-3 and fifth-seeded German Florian Mayer snuck past talented Belgian David Goffin 7-6 (7-2), 1-6, 6-3. The 2011 champion Mayer is seeking his second title here in three years.
One other Day-4 second-round result saw Garcia-Lopez overcome Ukrainian qualifier Sergiy Stakhovsky 1-6, 6-3, 6-4.
The other quarterfinals will pit second-seeded Frenchman Gilles Simon against German Daniel Brands, Mayer versus the 2007 Bucharest runner-up Hanescu and eighth-seeded Serb Viktor Troicki against Czech Lukas Rosol.
Simon is the reigning Bucharest champion, having beaten Italian Fabio Fognini in last year's finale. The former top-10 Frenchman also titled back-to-back here in 2007 and 2008.
This week's champion will collect $96,000.