MONTRÉAL, Canada - Former runner-up Maria Sharapova begins her 2014 Rogers Cup challenge against WTA Rising Star Garbiñe Muguruza, while later on Central top seed Serena Williams takes on Samantha Stosur.
Wednesday, Second Round
 Maria Sharapova (RUS #6) vs. Garbiñe Muguruza (ESP #27)
Head-to-head: Sharapova leads 2-0
In the quarterfinals of this year's French Open, Maria Sharapova teetered - not for the first time in the tournament - dangerously close to elimination. However, as she has so often in her career, the Russian summoned her best tennis when she needed it most to subdue and eventually overcome an inspired Garbiñe Muguruza.
Sharapova would go on to lift the title in Paris, but to the surprise of many was unable to follow it up with a meaningful run at Wimbledon. Now the Russian returns to the North American hardcourts where she honed her game as a junior to begin her preparations for the US Open.
First up is a rematch with Muguruza, who, like Sharapova, has struggled to fully build on her French Open form, falling in the first round at Wimbledon and losing badly last week to Angelique Kerber in the quarterfinals of Stanford.
 Serena Williams (USA #1) vs. Samantha Stosur (AUS #21)
Head-to-head: Williams leads 6-3
Such is the strength of the draw at the Rogers Cup this year that top seed Serena Williams' first match is against a fellow Grand Slam champion. However, at present, Stosur is not playing the sort of tennis that took her to US Open glory three summers ago, underlined by her first round defeat to World No.406 Naomi Osaka at the Bank of the West Classic.
Williams meanwhile banished the ghosts of Paris and London by collecting the title in Stanford, passing a couple of gut checks - most notably in the quarterfinals against Ana Ivanovic - along the way.
As against most of her rivals, Williams holds the edge in the head-to-head, winning six of their nine encounters, one of which came in the 2011 Rogers Cup final.
Stat to watch: Stosur is one of three players to have beaten Williams in a Grand Slam final. The other two are her sister Venus and Maria Sharapova.
Also on court...
No.2 seed and 2012 champion Petra Kvitova's meeting with Casey Dellacqua follows Williams and Stosur on Central, while over on Banque Nationale Jelena Jankovic, Venus Williams and Ana Ivanovic are all in action.