Hingis and Pennetta lost the first set despite having a 3-0 lead but cruised through the second set, and from 4-3 down in the match tie-break won seven of the next nine points to finish off their 4-6, 6-2, 10-6 triumph over this year's Brisbane and Dubai champions. Next up for them are Anastasia Pavlyuchenkova and Lucie Safarova.
"We have good chemistry and are a good fit," Hingis said. "We complement each other. Today was not always the best tennis, but a win is a win, so I'm happy."
Hingis and Pennetta, who were runners-up in Eastbourne earlier this year in their one previous outing, have had success in Montréal in the past with other partners. Hingis was victorious in 1998 with Jana Novotna and 2000 with Nathalie Tauziat and Pennetta in 2010 with Gisela Dulko.
Also moving on were fifth-seeded Russians Ekaterina Makarova and Elena Vesnina. Their 7-6(7), 6-3 triumph over Anabel Medina Garrigues and Yaroslava Shvedova avenged a loss to the Spanish-Kazakhstani duo in Madrid earlier this year in which they only managed four games.