Wimbledon champion Petra Kvitova and French Open winner Maria Sharapova suffered third-round shock exits while top seed Serena Williams avoided the upset bug Thursday at the WTA Montreal hardcourt tournament.
Russian Ekaterina Makarova upended second-seeded left-hander Kvitova 6-4, 1-6, 6-2, while diminutive Spaniard Carla Suarez Navarro stunned fourth-seeded Sharapova 6-2, 4-6, 6-2, following a third-set rain delay, at Uniprix Stadium.
Williams advanced by defeating Lucie Safarova 7-5, 6-4 to reach the quarter-finals.
Suarez Navarro, who is seeded 14th in Montreal and ranked 16th in the world, shrugged off two rain delays at the $2.4 million event and emerged with the victory over Sharapova who saw her preparations for the upcoming US Open suffer a huge setback.
"I couldn't find my rhythm from the beginning. Always had my back against the wall throughout the whole match," Sharapova said.
The former world No. 1 Sharapova, who'd won 11 of her previous 12 matches on tour, has now lost her last two three-set matches after winning 11 straight.
Suarez Navarro put on a crisp shot-making display as she cruised through the first set.
Sharapova, who had also started slowly but managed to rally against second-round opponent Garbine Muguruza, battled back from a 4-2 deficit in the second to force the decisive third set, but she had no answer for Suarez Navarro in the third.
"It was a tough match," Sharapova said. "I thought my opponent played a really good match.
"Even though I felt like I started feeling a little bit better, it wasn't enough in the end. Sharapova's wayward backhand on match point was her 49th unforced error of the contest. She converted just six of her 19 break point opportunities.
Sharapova said her inability to reliably put her first serve in play was a factor in the defeat, but not her only problem.
"Obviously you think a lot more about the second serve, which is a lot more difficult," she said.
"I was struggling with not just that today, but a lot of unforced errors from the baseline as well. Couldn't commit on the return. So I think it was a little bit of everything."
Sharapova said she wouldn't blame two rain delays for her inability to find her rhythm.
"I think I've been on the tour for way too long," she said. "I know what to expect and to know that anything can be thrown at you, whether it's another delay, weather, or something else. That's part of the game. That's never bothered me."
Now Sharapova has just over two weeks to hone her hardcourt game before the start of the year's last Grand Slam, the US Open at Flushing Meadows on August 25.
"There's quite a bit of time until then," Sharapova said, stressing that it's just a matter of fine-tuning a few things." Kvitova's first tournament since her Wimbledon triumph came to an abrupt end as she was bundled out of the tournament by Makarova.
The Czech star was the Montreal champion two years ago. It was a disappointing end to the week for Kvitova, who claimed her second Wimbledon title last month.
Williams fired 11 aces and won 76 percent of her first serve points against the Czech in the 90 minute match on centre court. The American world number one next faces former world number one Caroline Wozniacki, who beat Shelby Rogers earlier Thursday 6-1, 6-0.
Wozniacki is currently riding an eight-match winning streak, which includes a title in Istanbul last month. The Danish star will face the sweet-swinging Suarez Navarro in Friday's quarter-finals.