Venus Williams rebounded from a shaky second set to defeat Anastasia Pavlyuchenkova 6-1, 3-6, 6-2 in the first round of the Rogers Cup on Tuesday.

Scoreboards went dark due to a power outage that affected 200,000 customers in the area, but the matches were able to go on as scheduled.

Elena Vesnina stepped in as a replacement for the ailing Andrea Petkovic and beat Camila Giorgi 6-4, 3-6, 6-2. Petkovic, the 16th seed, was unable to play because she was sick.

"I pushed it back until the end and really tried to get healthy," she said in a statement. "But I had a temperature and a fever and it's too risky to play like that in these kinds of conditions.