Tenth-seeded David Goffin of Belgium secured a second-round berth after overcoming compatriot Steve Darcis 6-2, 6-1 at the ATP Monte-Carlo tennis Masters.
Goffin showed his dominance throughout the first-round match, which only lasted 72 minutes and 30 unforced errors were much to blame for Darcis' lopsided loss on Sunday, reports Xinhua news agency.
Trailing 1-5 in the first set, Darcis managed to save two set points, before Goffin held his serve in the eighth game to build a solid start.
He went on to take all three games early in the second. A furious Darcis threw his racket onto the ground. Goffin conceded only one game to make it into the last 32.
"I played well from the start and was solid in long rallies. It's never easy to take on a friend. I'm very satisfied with my performance," said Goffin, who awaits Nicolas Almagro or a qualifier in the second round.
After beating Malek Jaziri of Tunisia 6-2, 6-2, French player Gilles Simon also booked a second-round encounter with second seed Novak Djokovic, who enjoyed a first-round bye.
Joao Sousa of Portugal eased past German player Florian Mayer 6-3, 6-2.
Third-seeded Stan Wawrinka made good preparation for his singles appearance in the tournament as he and Italian partner Fabio Fognini eliminated Max Mirnyi and Daniel Nestor 6-4, 7-6 (2) in the doubles first round.
The ATP Monte-Carlo Masters will run until April 23, with Roger Federer and Kei Nishikori absent from the tournament.