TORONTO (AFP) - Defending champion Novak Djokovic returned to tennis for the first time since Wimbledon and broke Canadian hearts with a 6-4, 6-4 second-round win over local Frank Dancevic.

The Serbian third seed and the Canadian of Serb heritage fired up their serves from the start, with Djokovic finding his precision return game to make the difference in his first visit to Toronto.

"I knew I was playing the home player, a big hope," said the Australian Open champion. "I've known Frank a long time and he always plays well here.

"I did what I needed to win, so I'm happy."

Djokovic secured the opening set with a break and stayed in focus to secure a 4-2 lead in the second

But Dancevic, who had knocked off Mario Ancic 24 hours earlier, saved a match point in the eighth game and broke Djokovic before the Serb broke back a game later for the win under threatening skies.

Djokovic, who beat Roger Federer and Rafael Nadal on the way to the title in Montreal a year ago, said he is taking his return to summer hardcourts slowly.

"I'm not looking at ranking points, I'm just trying to enjoy. I've had my best results on hardcourts."

Former champion Andy Roddick had to work harder than expected to suppress an upset bid from France's Nicolas Mahut with a 6-1, 6-7 (6/8), 6-3 second-round win.

The 2003 titlist showed some signs of rust as he competed for the first time in nearly a month following a second-round loss at Wimbledon, which was followed by more work to rehab a right shoulder injured two months ago in Rome.

"I feel good for the first time since probably we finished our Davis Cup tie in April," said the sixth seed.

"I might have played decent at Wimbledon had I been prepared. But I went there kind of hoping, and I knew I was doing that. It's unfortunate, but I've been pretty lucky."

Spain's 13th seed Fernando Verdasco and number 16 Czech Tomas Berdych advanced on a day interrupted for a short period by showers and the fear of lightning.

German Tommy Haas, a quarter-finalist last week at the Indianapolis event where he ended with a loss to eventual champion Gilles Simon, was another early winner.

The 30-year-old beat Spain's Carlos Moya 6-3, 6-2.

Haas underwent a third operation on his right shoulder seven months ago and reached the last eight in four days ago.

If the shoulder says at one stage 'there's no more' I'll have to deal with that," said the 30-year-old. "It has already tried it three times, and I'm still here, so its still pretty good."

Canadia-born American Jesse Levine earned a Wednesday match with second seed Nadal after beating Canada's Peter Polansky 6-2, 6-4.

The Spaniard, who beat world No.1 Federer in the Wimbledon final, will be playing for the first time this summer on cement as the Beijing Olympics and US Open approach.

"I'm looking forward to playing," said Levine, ranked 121 places lower than Nadal. "I always watch him on TV, so it's good to play him on stadium court tomorrow."

Swedes collected a hat-trick with first-round wins from Robin Soderling, lucky loser Thomas Johansson and 36-year-old Jonas Bjorkman.