John Isner used his big serve to down Vasek Pospisil 7-6 (1), 4-6, 6-3 and eliminate the last Canadian from the singles draw Wednesday night at the US$4.1 million men's Rogers Cup.

Isner, the 16th seed, advanced to the third round of the hardcourt Masters 1000 series event with his second win in as many weeks over Pospisil, a Vernon, B.C. native who fell to the six-foot-10 American last week in Washington, D.C.

Pospisil, ranked 45th, reached the semifinals the last time the Rogers Cup was held in Montreal in 2013, but this one ended against one of the ATP Tour's biggest servers despite the support of the packed centre court grandstands at Uniprix Stadium.

The first set started and ended poorly for Pospisil. He double faulted on break point in the opening game, but evened the set at 2-2 with a remarkable service return on break point. It went to a tiebreaker, where Isner aced all four of his serves and Pospisil double faulted on set point.

The Canadian opened the second set with a service break and held his own to tie the match.

Isner finally broke for 4-2 in the third, when Pospisil double faulted to give the American advantage and then hit a groundstroke long on break point.

Pospisil had a break point in the next game, but Isner powered his first serve in to go to deuce and ended it with two aces.

Earlier, Kei Nishikori followed his tournament victory in Washington, D.C. last week with a 6-3, 6-3 win over Pablo Andujar. The fourth-seeded Nishikori posted his ATP Tour-leading 27th hardcourt win of the year.

Nishikori reached the U.S. Open final last September and hopes to go a step further when he returns to Flushing Meadow on Aug. 31.

"I'm going to try to go to the final again, but I know it's a new U.S. Open this year," he said. "Just playing one match at a time and trying to focus from first match, and see what I can do again."

David Goffin, seeded 13th, will be Nishikori's opponent in the round of 16 on Thursday after a 6-4, 6-4 win over Sam Querrey.

Rafael Nadal, coming off a win on clay at Hamburg two weeks ago, got his tournament started with a 7-6 (4), 6-3 win over Sergiy Stakhovsky. He next faces Mikhail Youzny, who upset ninth-seeded Gilles Simon 6-1, 6-4.

Nadal, a winner of 14 career grand slam events, has slipped to ninth in the world after an up-and-down year. But back to full health, Nadal hopes to climb back to the top.

"I won in Hamburg a couple weeks ago and this was an important victory here," he said. "Six consecutive (match) victories, that didn't happen very often during the season.

"That's a positive moment for me."

American Jack Sock downed 14th-seeded Grigor Dimitrov 5-7, 7-6 (5), 7-5 to advance to a meeting with top-seeded Novak Djokovic.

Gilles Muller upset Gael Monfils, the 15th seed, 6-3, 3-6, 7-6 (4) and next gets second seeded Andy Murray, who beat Tommy Robredo 6-4, 7-5.

Jeremy Chardy downed Leonardo Mayer 6-4, 7-6 (4) to set up a third round meeting with six-foot-11 Ivo Karlovic, the 36-year-old who ousted Canada's Milos Raonic on Tuesday night.

A pair of qualifiers got the to third round as Donald Young knocked off fifth seeded Tomas Berdych 7-6 (5), 6-3 and Ernests Gulbis beat Lukas Rosol 6-2, 5-7, 6-3.