Heather Watson won't get Serena Williams rematch

British number Heather Watson failed to book a rematch with Serena Williams after falling at the second hurdle of the Rogers Cup.

The 23-year-old, who came so close to eliminating eventual winner Williams from Wimbledon last month, made light work of Irina Falconi in the opening round but could not keep Germany's 16th seed Andrea Petkovic under wraps in Toronto on Wednesday.

Petkovic took full advantage of Watson's faltering first serve to win 6-4 6-3 and it is she who will now face top seed and world number one Williams.

Second seed Simona Halep held all 10 of her service games en route to a 6-3, 6-4 win over former world number one Jelena Jankovic on Wednesday.

Playing for the first time since last month's Wimbledon tournament, Halep fought off all three break points she faced and won 80 percent of her first serve points in the 81 minute second-round match.

"My serve was pretty good today," Halep said. "I tried to be aggressive and take the ball as soon as possible, because I know she has good defence. And I tried to keep my first serves in because she returns well, too. And I also tried to play her forehand more, because she has a very strong backhand.

Live ATP Masters Tennis

"I knew I had to make her run a lot, open the court and finish the points when I could."

Romania's Halep advances to the third round where she will face number 13 seed Angelique Kerber who easily beat qualifier Monica Puig of Puerto Rico 6-2, 6-3.

Two-time Australian Open winner Victoria Azarenka upset third seeded Petra Kvitova 6-2, 6-3 to reach the third round.
The 26-year-old Azarenka won 64 percent of her second serve points to just 35 percent for Kvitova in the 88 minute match on center court. 

Fourth seeded Caroline Wozniacki of Denmark and Wimbledon finalist Garbine Muguruza were also sent crashing out of the event.

The eighth seeded Muguruza lost 7-5, 6-1 to Lesia Tsurenko. The Ukrainian qualifier needed only 77 minutes to beat the 21-year-old Muguruza who has risen to number nine in the world after her run to the final at Wimbledon.

Fifth-seeded Ana Ivanovic of Serbia and sixth seeded Agnieszka Radwanska also advanced to the third round.