Gauff's serve changes are still embedding into her tennis. But she has other ways to win when the double faults start.

It’s not often that the world No. 2 goes two months without winning a match, but that’s the reality Coco Gauff was facing late Tuesday night in Montreal, on the cusp of a third consecutive loss, this time in her opening duel at the Canadian Open.

Gauff had to overcome 23 double-faults to win for the first time since the French Open final, outlasting fellow American Danielle Collins 7-5, 4-6, 7-6 (2) in the second round of the National Bank Open.