Former world number one Jelena Jankovic suffered a swift exit at the Rogers Cup Monday, falling 6-1 6-3 to Germany's Julia Goerges on a day where a pair of other top seeds fell.
France's Marion Bartoli and Russia's Svetlana Kuznetsova also suffered surprise first-round exits, both players eliminated by a pair of gritty qualifiers.
Goerges had not won a set in two previous meetings with the 15th seeded Jankovic but the 22-year-old German struck early and never really allowed her opponent any chance to get back in the 71-minute match.
"It's always tough to play a player like Jelena, she's a great fighter, great player and a former world number one so you always have to play your best," said Goerges.
"Just go out there and fight and that's what I did today and obviously it worked pretty well."
Goerges, who has been hailed as the 'new Steffi Graf', will play the winner of Tuesday's match between Serena Williams and Alona Bondarenko.
World number nine Bartoli fell 6-3 6-3 to Kazakhstan's Galina Voskoboeva while Kuznetsova followed her out of the $2 million tournament when she was upset 4-6 6-4 6-3 by Romania's Simona Halep.
Bartoli had trouble moving around the court and getting her usually strong backhand working against Voskoboeva.
"When you commit so many mistakes like I did today, it's really hard to win a match," Bartoli told reporters.
"It was really like my game was not at the level I'm supposed to play regarding my ranking. That was the main problem."
Samantha Stosur of Australia overcame a slow start to get past Japan's Ayumi Morita 4-6 6-2 6-3.