Toronto - Second seed Stan Wawrinka matched his best career result at the Toronto Masters on Thursday after a 7-6 (7/3), 6-2 defeat of American Jack Sock put him into the quarter-finals.
It was the first time in five years that the double Grand Slam champion Swiss had reached the last eight in Canada; he went out in an opening match a year ago to Nick Kyrgios and got to the third round in 2014.
The 31-year-old, who will depart for the Olympics in Rio de Janeiro as soon as his run in Canada is complete, saved all three break points he faced against the 16th-seeded Sock.
The first set provided a challenge, with Wawrinka winning it in a decider to seize the match momentum.
"You need to be careful in tiebreaks, and really focus," said Wawrinka. "I feel positive now after this win - let's see what happens."
Wawrinka, winner of 30 matches this season, said he is looking forward to his third Olympics even as dropouts continued with the Thursday withdrawal of Ukrainian Sergiy Stakhovsky.
"I have lots of good memories from Beijing, 2008 (he won doubles gold with Roger Federer). I'm looking forward to playing again. I really enjoyed the experience."
The French and Australian Open champion next plays South African Kevin Anderson, who overhauled 12th seed Bernard Tomic 4-6, 6-3, 6-4 in two hours, firing 26 aces and saving eight of nine break points in the comeback effort.
Japan's third seed Kei Nishikori reached the quarters without the loss of a set as an injury from Wimbledon fades away.
Asia's top player advanced over Rajeev Ram 6-3, 6-4.
"I think it's good, not maybe 100 per cent yet but feeling pretty strong," he said of a rib problem.
"I'm playing my first matches in three or four weeks ago. I'll have to see after couple more matches, but right now I feel good."