Toronto - Novak Djokovic made a winning return on Wednesday in his first match back since a shock third-round defeat at Wimbledon, defeating Gilles Muller in straight sets to advance at the Toronto Masters.
The Serbian world number one took the first step toward a possible 30th career Masters 1000 title as he beat Muller 7-5, 7-6 (7/3) in just under two hours.
"It's tough playing the first hardcourt match since March," said Djokovic. "It was hot and that made the ball move very fast.
"It was hard to control, it was not easy to play. But I managed to stay tough.
"I was disappointed to lose serve twice in the second set when I was up a break, but I was just glad to close this out in straight sets."
Djokovic brings a formidable record back to Canada, winning 18 of 21 matches at the event which alternates between Toronto and Montreal each year. The number one has advanced to the quarter-finals or better in eight of nine years in Canada.
Djokovic stands 47-4 on the season, with six titles. He was beaten a year ago in the Canadian final by Andy Murray.
Japanese third seed Kei Nishikori joined Djokovic as a winner, defeating Dennis Novikov 6-4, 7-5.
"I knew I was going to get up-and-downs because I haven't played matches long time," Nishikori, who retired in the Wimbledon fourth round, said.
"I didn't practise much, but I played good tennis."
Sixth seed Dominic Thiem is heading back to Austria for scans on a troublesome hip after quitting after just 20 minutes in a 4-1 loss to Kevin Anderson.
"I felt it since like two weeks," Thiem said. "It didn't get worse. I decided to go out and to try, but yeah, obviously it didn't work out against such a good player.
"It's the time to just give the body a little bit of time to really get 100 per cent," said one of the first ATP players to pull out of the Rio Olympics. "This is not the way I want that the body feels."
Belgian seventh seed David Goffin advanced when Sam Querrey stopped while trailing 6-4, 2-1 with back pain.
American Ryan Harrison knocked out ninth-seeded compatriot John Isner 7-6 (7/3), 6-7 (4/7), 6-4 while Australian 12th seed Bernard Tomic advanced past Canadian Steven Diez 6-3, 7-6 (7/4).
French 13th seed Lucas Pouille lost to Rajeev Ram 6-4, 7-6 (7/5).
Results on Wednesday in the Toronto ATP Masters hardcourt tennis tournament (x denotes seeded player):
Milos Raonic (CAN x4) bt Lu Yen-hsun (TPE) 6-3, 6-3
Grigor Dimitrov (BUL) bt Denis Shapovalov (CAN) 6-4, 6-3
Jack Sock (USA x16) bt Donald Young (USA) 6-4, 6-3
Jared Donaldson (USA) bt Fabio Fognini (ITA) 6-3, 3-6, 6-3
Ivo Karlovic (CRO) bt Marin Cilic (CRO x8) 6-4, 7-6 (7/3)
Gael Monfils (FRA x10) bt Vasek Pospisil (CAN) 7-6 (8/6), 6-0
Novak Djokovic (SRB x1) bt Gilles Muller (LUX) 7-5, 7-6 (7/3)
Bernard Tomic (AUS x12) bt Steven Diez (CAN) 6-3, 7-6 (7/4)
Radek Stepanek (CZE) bt Peter Polansky (CAN) 7-6 (7/5), 6-4
Ryan Harrison (USA) bt John Isner (USA x9) 7-6 (7/3), 6-7 (4/7), 6-4
David Goffin (BEL x7) bt Sam Querrey (USA) 6-4, 2-1 retired
Rajeev Ram (USA) bt Lucas Pouille (FRA x13) 6-4, 7-6 (7/5)
Kei Nishikori (JPN x3) bt Dennis Novikov (USA) 6-4, 7-5
Kevin Anderson (RSA) bt Dominic Thiem (AUT x6) 4-1 retired