MONTREAL: Canadian teenager Victoria Mboko took down top-seeded American Coco Gauff 6-1, 6-4 on Saturday, thrilling the home crowd as she reached the quarterfinals of the WTA 1000 tournament in Montreal.

The 18-year-old wild card saved all four break points she faced, and broke reigning French Open champion Gauff three times on the way to a comprehensive victory in just 62 minutes.

Gauff, who had a combined 37 double faults as she struggled through her first two matches, was caught flat-footed as the Canadian teen raced through the first set in 25 minutes.

Gauff buckled down in the second, but she was unable to convert three break chances in the seventh game — coming up short on a drop shot and smacking a forehand into the net on the first two.

She gained anther chance only to hit a service return long, then flew a volley wide to give Mboko a game point, duly converted when Gauff fired a forehand long.

Down 15-30 in the ninth game, Mboko leveled at 30-30 with a blistering backhand, then closed out the hold for a 5-4 lead.

Serving to stay in the match, Gauff fell in a quick 0-30 hole and double-faulted to give Mboko a match point, on which the American hit a backhand into the net.

Mboko will next play either China’s Zhu Lin or Spain’s Jessica Bouzas Maneiro.

Zhu, once ranked as high as No. 31 in the world, has dropped to 493rd after missing the last five months of 2024 and another three months earlier this year with an elbow injury.

In early matches, former Wimbledon champion Elena Rybakina outlasted Dayana Yastremska 5-7, 6-2, 7-5 to book a quarterfinal clash with Marta Kostyuk.

Kazakhstan’s Rybakina, the 2022 Wimbledon champion who won her first title in more than a year at Strasbourg in May, was slowed by nine double faults.

But she ultimately had enough to get past Ukraine’s Yastremska — who was coming off a straight-sets victory over eighth-seeded American Emma Navarro.

Yastremska fell behind an early break in the first set, but took advantage of Rybakina’s early serving woes to break back, and broke again to take the opening set in a game that Rybakina had led 40-0.

Rybakina, seeded ninth, bore down after that, breaking Yastremska twice to take the second set.

Another untimely double fault cost her a break in the third, but she broke Yastremska for the second time in the set to take a 6-5 lead and held on to seal it on her fourth match point.

She’ll face another Ukrainian in Kostyuk, who came from behind to beat American McCartney Kessler 5-7, 6-3, 6-3.