Donna Vekic of Croatia downed Canadian Eugenie Bouchard 6-3, 6-4 in first-round play at the Rogers Cup on Tuesday.
The 21-year-old Vekic, ranked 51st in the world, will face third-seed Angelique Kerber in the second round.
Playing in her main draw debut at the Rogers Cup, Vekic broke the 70th-ranked Bouchard six times and won 17-of-27 first-serve points at Aviva Centre.
Bouchard started the match on the wrong foot, getting broken in the first game after a lengthy back-and-forth. Vekic held serve then broke Bouchard again for a 3-0 lead.
Bouchard was 2 for 3 on break points during the first set but Vekic broke the Canadian four times, including the deciding game _ a 10-minute long affair that saw the opponents hit deuce six times.
Bouchard fired two aces but double faulted five times to Vekic's three in the first set. She had 19 unforced errors to Vekic's 10.