Navratilova has now won the doubles portion of this Canadian tournament five times. She partnered with Groenefeld to claim the championship in 2004.
The 49-year-old Navratilova and 24-year-old Petrova played together for the first time this week. They were unseeded.
Navratilova, who will turn 50 in October, will retire from tennis for the second time following the upcoming U.S. Open. which gets under way next week in New York.