Venus Williams booked her place in the quarter-finals of the Coupe Banque Nationale in front of a record crowd in Quebec.
The top-seeded American saw off Olga Savchuk 6-1 6-2 - reeling off 10 straight games as part of a thrilling show.
"Everything worked so well today," Williams said on the WTA's official website.
"When my first serve is going in that helps a lot. I was able to play so offensively off the first serve. Even though I lost serve a couple of times, it wasn't really from the serve, it was from the groundstrokes. It feels good to play like this going into the quarters."
It was a day to forget for second seed Ajla Tomljanovic and Timea Babos, seeded eighth, as they both crashed out.
Croatian Tomljanovic suffered a 6-3 3-6 6-3 defeat to Andrea Hlavackova, while Mirjana Lucic-Baroni defeated Hungary's Babos 7-6 (7/3) 6-2.
In the day's other second-round clash, Lucie Hradecka hit back from a set down to overcome Czech compatriot Barbora Krejcikova 3-6 7-5 6-2.