Simon easily got by Daniel Brands 6-1, 7-5. He lost six points on serve in the first set and posted a pair of breaks in the second in moving into the semifinals.
Guillermo Garcia-Lopez outlasted Tipsarevic for a 6-3, 4-6, 6-4 victory that took more than 2 1/2 hours. Garcia-Lopez, who improved to 2-0 lifetime versus the world No. 10 Tipsarevic, lost seven points over five games serving in the third set.
Fifth-seeded Florian Mayer, losing his serve once, came away with a 6-3, 7-6 (7-3) win over Victor Hanescu, but Lukas Rosol took out eighth-seeded Viktor Troicki 6-3, 6-1 by fighting off all 10 break points he faced.
Simon goes against Rosol, who he beat in their only previous meeting, in Saturday's semifinals while Mayer and Garcia-Lopez square off in the other semi. Mayer is 1-0 lifetime against Garcia-Lopez.
The tournament is formally known as the BRD Nastase Tiriac Trophy.