Djokovic is playing his first tournament since Wimbledon
World number three Novak Djokovic began the defence of his Toronto Masters title with an impressive 6-4 6-4 win over Canadian Frank Dancevic.
The Australian Open champion was joined in the third round by 2003 Toronto champion Andy Roddick.
American Roddick was made to fight before emerging with a 6-1 6-7 (6-8) 6-3 win over France's Nicolas Mahut.
Both players were in action for the first time since suffering shock second-round defeats at Wimbledon.
Roddick lost to Janko Tipsarevic, while Djokovic went out to Marat Safin.
The world number three took time to shake off the rust on Tuesday against a player who had beaten Mario Ancic in the first round.
But the 21-year-old Serb broke once to take the first set and then recorded an early break in the second.
Dancevic, urged on by the partisan crowd, staged a late rally by breaking back and holding serve.
But Djokovic responded with the decisive break to seal the match in 77 minutes.
"I was aware he had nothing to lose, the big Canadian hope playing in front of his crowd with big support," said Djokovic.
"Always the first match is the trickiest one, trying to keep the balance.
"There were some things that I was not really happy about but it is still only the first match."
Roddick, who been troubled by a shoulder injury this season, looked on his way to a straight-sets win but Mahut fought back to level the match in a tie-break.
However, the American broke early in the third set and sealed the win with his 18th ace.
"I thought I moved well and most importantly I felt well physically," stated Roddick.
"Physically I feel good for the first time since our Davis Cup tie in April. Hopefully my problems are behind me and I can play good tennis again."
Frenchman Gilles Simon crushed 18-year-old American qualifier Donald Young 6-1 6-3 to set up a second-round meeting with world number one Roger Federer on Wednesday.
French Open and Wimbledon champion Rafael Nadal will face Jesse Levine after the American qualifier beat Canadian wildcard Peter Polansky 6-2 6-4.