QUEBEC CITY, Canada - Varvara Lepchenko sent No.1 seed Aryna Sabalenka crashing out of the Coupe Banque Nationale in straight sets 6-4, 7-6(5), continuing a day of upsets in Quebec City.

Read more: Marino dispatches Maria in Quebec City upset

Sabalenka came into the tournament looking to carry on her great results from the US Open series, which culminated in a maident WTA title at the Connecticut Open in New Haven, a semifinal run in Cincinnati as well as a fourth round appearance in her US Open main draw debut.

But she ran up against a motivated Lepchenko, who posted a quarterfinal finish at last week’s Chicago WTA $125K event. The American needed just one break of serve to claim the first set, getting the lead at 3-2, and fought off three break-back points at 5-3 to power ahead.

The second set started out just like the first, including another Lepchenko break at 3-2 - but this time Sabalenka came roaring back, saving match point at 5-4 and leveling the match. The pair marched into the tiebreaker, where the American quickly built up a 4-0 lead.

Sabalenka tried to put together another comeback effort, saving two match points and cutting into Lepchenko’s lead, but Lepchenko kept her nose in front and finally closed out the match after an hour and 32 minutes.

Up next, Lepchenko will face Czech qualifier Marie Bouzkova, who defeated Sesil Karatantcheva in straight sets earlier in the day.

Sabalenka wasn’t the only seed to tumble at Quebec City; No.7 seed Tatjana Maria was upset by Rebecca Marino in straight sets, while Ons Jabeur handed No.6 Lucie Safarova a heartbreaking three-set loss.