Sam Querrey got past Martin Klizan in straight sets 6-3, 6-3 in the first round of the Rogers Cup men's tournament on Monday.
Also, France's Gilles Simon defeated Italy's Andreas Seppi in straight sets 6-2, 6-4.
Spain's Tommy Robredo needed three sets to top countryman Feliciano Lopez 6-3, 3-6, 6-3. Robredo will face third-ranked Andy Murray in the second round.
On the main court, Gael Monfils of France beat Italy's Fabio Fognini in straight sets 6-3, 6-1. Monfils broke Fognini's serve four times and finished with seven aces to Fognini's three.
"I wanted to start off this tournament well," said Monfils, who has yet to win a Grand Slam in his career. "It was not a great match, but I didn't play bad. I was solid. I didn't give away any points."
The Frenchman will face Gilles Muller in the second round.
"I'm looking forward to that match because I've known him for a long time," said the 28-year-old Monfils. "I know he's a good player. He plays well. He's very aggressive and has a good serve."
Muller defeated Canada's Philip Bester in straight sets 6-2, 6-3.
Bester struggled against Muller's powerful serve. Bester also had unforced errors throughout and never managed to break Muller's serve.
Earlier on Monday, Vancouver's Filip Peliwo lost to Ukraine's Sergiy Stakhovsky in three sets. Peliwo lost 6-1, 5-7, 6-2 to Stakhovsky.
In doubles, Murray and India's Leander Paes defeated Kevin Anderson and Jeremy Chardy in straight sets 6-3, 6-1.
Rafael Nadal and Fernando Verdasco beat Tomas Berdych and Jack Sock in three sets and Novak Djokovic and Janko Tipsarevic downed Seppi and Viktor Troicki 6-4, 6-3.