MASON, Ohio -- Fresh off their inspired performances at the Rogers Cup, Canadians Milos Raonic and Vasek Pospisil are into the second round of the Western & Southern Open.

Raonic, who dropped Sunday's final in Montreal to Rafael Nadal, defeated Jack Sock 3-6, 6-4, 6-3 on Tuesday night to advance.

The 12th seed from Thornhill, Ont., Raonic lost to the American in Memphis in February after winning the San Jose event the previous week for the third year running.

Raonic, now ranked a career-high 10th on the ATP Tour after beating Pospisil in the Rogers Cup semifinals, disposed of Sock in just under two hours. He will meet Serbia's Janko Tipsarevic in the next round.

Pospisil, now also ranked a career-best at No. 40, advanced when France's Gilles Simon retired with an injury.

Simon was trailing 6-3, 1-1 when he ended the match.

"It was a strange match," Pospisil said. "I started out well but I noticed that something was going on with him, I think it might have been the hip.

"It was difficult to play from that point. It was fortunate for me and unfortunate for him."

The Vernon, B.C., native needed just 36 minutes to sweep the opening set against Simon, who lost his fifth match in a row and hasn't won since mid-June.

Pospisil faces Belgium's David Goffin in the next round.

"The match will be tough and I don't see a clear favourite," Pospisil said. "He's a dangerous player, very talented, and has beaten some top players. We'll have to see."

Meanwhile, John Isner defeated Florian Mayer 6-3, 6-4, and Grigor Dimitrov defeated Brian Baker 6-3, 6-2. Third-seeded David Ferrer edged Ryan Harrison 7-6 (5), 3-6, 6-4.

On the women's side, second-seeded Victoria Azarenka held off an upset bid by qualifier Vania King to pull out a 6-1, 7-6 (6) win and advance to the third round.

Azarenka rallied from a 3-0 deficit in the second set to force the tiebreaker against the 140th-ranked American.

Azarenka, who has been bothered by a lower back injury, won her first match since losing to Samantha Stosur in the finals of the Southern California Open two weeks ago.

"I think the beginning of the second set wasn't very good for me," Azarenka said. "There were quite a few unforced errors and just really fast mistakes, which didn't happen in the first set."

Varvara Lepchenko advanced with a 6-2, 2-6, 6-2 win over Flavia Pennetta, and Jamie Hampton needed three sets to overcome Anastasia Pavlyuchenkova 7-5, 4-6, 6-3.

Alize Cornet rallied past Ana Ivanovic 2-6, 7-6 (8), 6-4.

Sorana Cirstea, the 21st-ranked Romanian who lost to No. 1 Serena Williams in the finals of the Rogers Cup in Toronto on Sunday, withdrew from her first-round match against Yanina Wickmayer.

Cirstea was replaced by No. 43 Monica Niculescu, who lost in this past weekend's qualifying but stayed around in case a spot opened up in the singles main draw and to play doubles. The Romanian capitalized on her second chance with a 6-1, 6-2 win over the 58th-ranked Wickmayer.

No. 10 seed Caroline Wozniacki easily advanced with a 6-1, 6-1 win over Shuai Peng.