Canadian qualifier Brayden Schnur punched his ticket to the ATP New York Open final by outlasting US journeyman Sam Querrey 7-6 (9/7), 4-6, 6-3 on Saturday.

Schnur, a 23-year-old from Montreal ranked 154th in the world, defeated 10-time ATP title-winner Querrey in one hour and 54 minutes in the semi-finals.

He will try to complete a fairy-tale championship run Sunday against American Reilly Opelka, who outgunned top seed John Isner in three sets 6-7 (8/10), 7-6 (16/14), 7-6 (7/4) in the other semi-final.

The all-American showdown set a Tour record for the most combined aces in a three set match with 81. The previous record was 71 set by Nick Kyrgios and Ryan Harrison earlier this year in Brisbane.

Schnur, the last alternate in the qualifying draw, had been winless in five career tour-level matches.

World number 49 Querrey, 31, was in his first ATP semi-final since last year in New York, when he lost to South African Kevin Anderson in the final.

Schnur denied Querrey’s first four break chances on set points in the 10th game then held to 5-5 on his fifth ace of the match as they battled into a tie-breaker.

Querrey double faulted to 4-4 and Schnur grabbed three set points before finally breaking through to claim the first set after 53 minutes.

Schnur broke Querrey in the second game of the second set on the way to a 3-0 lead, but the US veteran roared back to win six of the next seven games and force a third set.

The Canadian jumped ahead 3-0 in the final set, fired his 12th ace to hold for a 5-2 lead and held again in the last game to advance.

In the other semi, Opelka survived five match points in a second set to send the contest to a third and final set.

The two hour, 31 minute serving duel saw Opelka blast 43 aces compared to 38 for the hard-hitting Isner.

Opelka, who also beat Isner in the opening round of the 2019 Australian Open, won 91% of his first serve points and was never broken.

Isner was seeking his 15th ATP title and first since winning last year in Atlanta.

But Isner failed to capitalize on numerous chances to close out the match in the second set tiebreaker.

Opelka won the tiebreaker 16-14, hitting a running crosscourt forehand to take the set 7-6.