Raonic's first clay-court win this season took just 72 minutes and came a week after his heroics in Canada's Davis Cup victory over Italy. The French Open, the only tennis Grand Slam played on clay, is slated to begin next month at Roland Garros.
"I did a lot of things well, especially only having a limited amount of preparation before here," Raonic said. "Davis Cup was a very good thing, but it was also very draining. It took a lot of energy to get through that weekend.
"So I was very happy with how I was able to prepare and play today. I came here feeling really good, especially playing as well as I did in Davis Cup."
Raonic, a native of Thornhill, Ont., served 15 aces and broke his French opponent three times to set up a match against Jarkko Nieminen, who thrashed Viktor Troicki 6-1, 6-2.
Roberto Bautista Agut also upset Gilles Simon 6-3, 7-6 (6).
Raonic's victory pushed his career record to 3-2 at the iconic Country Club venue and restored pride after his first-round loss a year ago to Spain's Albert Montanes.
"I played well today," said the 12th-seeded Canadian. "I've had four days of clay training and feel my game is off to a good start.
"It's a long clay season, my next goal is to win my next match."
Raonic lost to Nieminen in their only previous match at Bangkok last fall.
"I did a lot of things poorly in that situation," Raonic said. "But I feel like if I play and I keep going for it like I was today, I was able to dictate play a bit.
"If I can get ahead in the points, I can keep that advantage to me and I think I'm pretty good in that position."
Bautista Agut, meanwhile, was pushed a little harder, closing it out on his fifth match point when the 11th-seeded Frenchman hit a forehand into the net. The Spaniard will play either Florian Mayer or Benjamin Balleret.
"I didn't produce anything during that first set. In fact, I was tired. Long rallies were killing me," Simon said. "In every game I was giving him a couple of free points, which hurts a lot on clay because from his side there were not many free points."
It was Simon's fourth straight defeat after losing to Tommy Haas in the Sony Open quarter-finals and both singles matches in France's Davis Cup quarter-final loss to Argentina.
Fabio Fognini rallied to down 15th-seeded Andreas Seppi 3-6, 6-4, 6-4 in an all-Italian match after converting seven-of-10 break chances. He faces either Radek Stepanek or qualifier Albert Ramos.
In other first-round matches, there were wins for Nikolay Davydenko, qualifier Pablo Andujar and Frenchmen Benoit Paire and Edouard Roger-Vasselin.
Davydenko beat qualifier Daniel Brands 6-3, 6-4; Andujar scraped past Jeremy Chardy 6-7 (4), 7-5, 6-2; Paire won 6-4, 6-4 against Ivan Dodig, and Roger-Vasselin topped Robin Haase 6-3, 6-2.
Later, ninth-seeded Marin Cilic will play Horacio Zeballos.
Top-seeded Novak Djokovic will decide Tuesday whether he's recovered from his ankle problem to play either Mikhail Youzhny or Daniel Gimeno-Traver on Wednesday, when No. 2 Andy Murray takes on Roger-Vasselin.
— With files from The Associated Press.