Verdasco, the highest seed in action on Monday, started slowly before regrouping to beat his Belgian opponent 4-6 6-2 7-5 in two hours and 10 minutes.

The left-handed Spaniard, who was runner-up at the event in 2010, broke serve for the fourth time in the last game of the match to register his 11th win of the year.

Fellow seed Jurgen Melzer also advanced following a routine 6-2 7-5 triumph over Lukas Kubot, while French wildcard Paul-Henri Mathieu, ranked 352 after a long absence with a knee injury, crushed Donald Young 6-0 6-1 to leave the American winless in his last five events.

Australian Bernard Tomic also reached the second round by beating Denis Istomin of Uzbekistan 6-4 6-3 - his first win in three visits to the Monte Carlo Country Club.

World No.34 Philipp Kohlschreiber eased past French qualifier Guillaume Rufin 6-4 6-4, while Jarkko Nieminen beat fellow veteran Radek Stepanek 6-3 7-6 (7/3) to earn a second-round match against seven-time defending champion Rafael Nadal.

No.16 seed Alexandr Dolgopolov also prevailed following a 6-2 6-2 demolition of Juan Igancio Chela in the afternoon session, while Milos Raonic succumbed to clay court specialist Albert Montanes 6-2 3-6 6-3.