QUEBEC -- It was Vanier Cup euphoria for first year quarterback Michael O'Connor, kicking ace Quinn van Gylswyk and the rest of the underdog University of British Columbia Thunderbirds.

The 19-year-old O'Connor passed for 389 yards and van Gylswyk's fourth field goal with no time left was the game-winner as UBC edged the defending champion University of Montreal Carabins 26-23 in a thrilling Vanier Cup final on Saturday afternoon.

"I knew they weren't going to let us run the ball so I had to play well for my teammates if we were going to win this game," said O'Connor, considered by many to be Canada's best quarterback prospect since another Ottawa native more than a decade ago, Jesse Palmer.

"We came out hot in the first half. A bit sloppy in the second half when I'd like to have some throws back, but hey, we pulled out the W."

It was a stunning performance from a team that was 2-6 last season and went 6-2 in Canada West conference play this season under veteran coach Blake Nill, who was lured to UBC after building a powerhouse at the University of Calgary.

Nill, who coached St. Mary's to Vanier Cups in 2001 and 2002 and who became the first winner with two different teams, had to choke back tears. His Dinos had lost Vanier Cups at the same field, Telus Stadium at Laval University, three times.

"We made it tough on ourselves but that's what you expect from a young team," said the 53-year-old Nill. "This group of guys, I don't even think they were picked to make the playoffs in Canada West this year.

"What they have done is one of the most amazing things I've seen. I can't grasp it right now."

The Thunderbirds shot out to a 16-0 lead in the second quarter only to see the Carabins roar back to tie the game 23-23 on Samuel Nadeau-Piuze's diving catch in the end zone with 7:15 left to play.

UBC had a chance to kick the go-ahead points with just over a minute to play, but holder Trevor Casey dropped the snap to turn over the ball on downs. But two plays later, Anthony Blackwell intercepted at the Montreal 52 to give UBC a second chance.

It came down to a last-play field goal from the 20. Montreal won the 2014 Vanier Cup by blocking a final minute kick by the McMaster Marauders and did the same to beat Laval in the Quebec Conference final. This time, van Gylswyk made no mistake.

"We've been saying it would come down to me to end the game," said van Gylswyk, who was four for four on field goals. "It's just unbelievable."

It was a heartbreaker for fifth-year Montreal quarterback Gabriel Cousineau, who is normally not a prolific passer but, in his final college game, completed 31 of 45 passes for 391 yards and nearly engineered a comeback win.

"They came to stop the run so we knew we could throw it," said Cousineau. "They did a great job at the end stopping us.

"We fell short just by a little bit, but we had some fun out there for sure."

Marcus David caught a touchdown pass and Brandon Deschamps scored on a 44-yard run for UBC. Will Watson caught 12 passes for 171 yards.

O'Connor was named MVP of the game and Stavros Katsantonis was named best defensive player.

Cousineau threw TD strikes to Guillaume Paquet and Nadeau-Piuze and David Deschamps had three boots for Montreal. Sean Thomas-Erlington rushed for 110 yards.

A lively but less than capacity crowd of 12,557 seemed split between fans of the Carabins and those who wanted the Laval Rouge et Or's closest rivals to lose.