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

Top-seeded Coco Gauff survived an error-laden second-round test from Danielle Collins, prevailing 7-5, 4-6, 7-6 (2) in an all-U.S. matchup at the Omnium Banque Nationale on Tuesday in Montreal.

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.