Grigor Dimitrov of Bulgaria beat eighth-seeded Janko Tipsarevic 7-6 (3), 6-1 in the second round of the Monte Carlo Masters on Tuesday.
Dimitrov had seven aces and broke Tipsarevic's serve four times.
Stanislas Wawrinka of Switzerland, Marinko Matosevic of Australia and qualifier Albert Ramos of Spain advanced to the second round.
Wawrinka defeated Denis Istomin 6-3, 7-5, breaking the Uzbek's serve five times; Matosevic beat Fernando Verdasco of Spain 7-5, 6-3 to set up a meeting with eight-time defending champion Rafael Nadal and Ramos downed Radek Stepanek of the Czech Republic 6-3, 6-3.
Later, sixth-seeded Jo-Wilfried Tsonga will play Nikolay Davydenko and No. 7 Richard Gasquet will face Benoit Paire.
Top-ranked Novak Djokovic was set to announce if he will play after recently twisting his ankle.