Seeded players Fernando Verdasco of Spain, Jurgen Melzer of Austria and Alexandr Dolgopolov of Ukraine all won first-round matches at the Monte Carlo Masters on Monday.
The 13th-seeded Verdasco rallied to beat Olivier Rochus of Belgium 4-6, 6-2, 7-5 and will next play Ivan Dodig of Croatia. The Spaniard dropped serve twice in the first set but didn't face another break point.
"I've got to the final here before, so it's one of my favorite tournaments," said Verdasco, who was crushed 6-0, 6-1 by seven-time champion Rafael Nadal of Spain in the final two years ago.
The 15th-seeded Melzer and Dolgopolov, seeded 16th, had much easier matches.
Dolgopolov took only 58 minutes to defeat Juan Igancio Chela of Argentina 6-2, 6-2, breaking serve twice in each set to set up a match against Bernard Tomic of Australia.
The 19-year-old Tomic was happy with how he mixed sliced forehands with heavy groundstrokes in his 6-4, 6-3 win against Denis Istomin of Uzbekistan.
"Regardless of any surface, he's pretty hard to play against," Tomic said. "A lot of clay-court players play behind the line. But I think my tennis is something different. If I play my tennis, they struggle with my game - even on clay."
Melzer downed Lukasz Kubot 6-2, 7-5 after breaking the Pole five times. He will play Julien Benneteau of France, who topped Spain's Marcel Granollers 6-3, 3-6, 6-2.
Albert Montanes advanced with a 6-2, 3-6, 6-3 against big-serving Milos Raonic of Canada, who hit nine aces. The Spaniard next plays seventh-seeded Janko Tipsarevic of Serbia.
Paul-Henri Mathieu of France thrashed Donald Young 6-0, 6-1, breaking serve six times and clinching victory when the American sent a forehand long.
"I was happy the way I was moving, and I was keeping the ball in the court," said Mathieu, who is finding his way back after a long-term knee injury. "I don't have the knees of a 20-year-old anymore. But I'm able to play 100 percent without any problems. Things are improving."
Mathieu next plays Kei Nishikori of Japan or Spain's Albert Ramos, who was runner-up at the Grand Prix Hassan II on Sunday.
There were also straight-sets wins for Philipp Kohlschreiber of Germany, and Finland's Jarkko Nieminen.
Kohlschreiber won 6-4, 6-4 against Guillaume Rufin of France, while Nieminen beat fellow veteran Radek Stepanek of the Czech Republic 6-3, 7-6 (3) to set up a match against Nadal on Wednesday.
Nadal, the six-time French Open champion, is chasing his first title since winning at Roland Garros last year.
"I have lots of success on clay in the past, so I want to do well here," Nadal said. "I haven't won a title (for 10 months), but how many finals have I played?"
Nadal has lost to Novak Djokovic in seven consecutive finals, and he could face the top-ranked Serb in the final.
Djokovic is scheduled to play against either Italy's Andreas Seppi or Romania's Victor Hanescu.