Playing in his first competitive match since mid-July, Monfils won 62 of the 103 points in the match to take victory in just 52 minutes as he completed his comeback from ankle and biceps injuries in convincing fashion.
"It was two weeks of training because I sprained my ankle before Montreal, so you know, I wasn't sure what I would give tonight [Tuesday], and I was very pleased with the way I played tonight [Tuesday]," Monfils told the event's website.
Monfils, seeded 15th here, will now face Tommy Robredo in the third round after the fourth seed saw off Guillaume Rufin 7-6 (7-5) 4-6 6-3.
Eighth seed Juan Monaco survived a two-and-a-half hour contest with Nicolas Mahut, eventually winning 6-7 (4-7) 6-3 6-4 to set up a meeting with Alexandr Dolgopolov, who also had to come from behind in beating Daniel Gimeno-Traver 4-6 6-1 6-4.
But second seed Andreas Seppi crashed out, beaten 6-7 (5-7) 6-4 7-5 by American Steve Johnson.
Mardy Fish retired from the event feeling unwell midway through his match with Jarkko Nieminen. Nieminen was leading 7-5 6-7 (3-7) 3-2 at the time.
James Blake also took his leave after losing 7-6 (11-9) 2-6 6-3 to fifth seeded Benoit Paire, while fellow American Tim Smyczek lost 3-6 6-3 6-3 to seventh seed Fernando Verdasco.
Paire will face the ninth seeded Jurgen Melzer, who had an easy passage as Thiemo de Bakker withdrew early in their clash with a toe injury, while Verdasco will face Robin Haase, a 6-4 3-6 7-5 winner over Lukas Rosol.
There were also victories for Ricardas Berankis, Roberto Bautista Agut, Dmitry Tursunov and Alex Bogomolov Jr.