Canada's bench piled on top of Felix Auger-Aliassime after he fell behind the baseline.
The Canadians were able to lift the Davis Cup.
Auger-Aliassime said that they had dreamt of this moment.
Canada won the title for the first time on Sunday by beating Australia.
The winning point was secured by Auger-Aliassime when he defeated Alex de Minaur 6-3,4-6.
Seven years after leading Canada to the top of junior tennis, Auger-Aliassime and his teammates lifted the biggest team trophy in their sport.
"We wanted to be part of the team and help the country win the first title, so everything is just so crazy right now," he said.
The 19-year-old had dropped his singles matches this week and needed treatment on his back during a three-set loss in the semifinals to Lorenzo Sonego. The left-handed player moved quickly around the court, setting up angles to put away winners as he raced to a four-set victory.
After a great second half of the season, Auger-Aliassime went to Spain and completed a perfect week. He twice kept the Canadians alive after his teammate dropped the first singles match, and on Saturday he replaced his tired teammate for the decisive doubles point.
The doubles match wouldn't be needed this time. After his teammates poured onto the court, they got up and danced in a circle.
Canada had reached the final once before, falling to host Spain in Madrid in 2019.
The Canadians are a better team now that Auger-Aliassime is in the top six. The junior Davis Cup title was won by Auger-Aliassime and the senior Davis Cup title was won by Shapovalova.
Australia was attempting to win its 29th title and first since 2003 when Lleyton Hewitt was part of the title-winning team.
The Canadians were given a wild card into the field when Russia was suspended.
De Minaur said that they were very close. Wait until we get the same match up again. We want to prove that we can do it.
Canada will be difficult to beat if Auger-Aliassime and Shapovalov play.
The two young men have already been Grand Slam semifinalists. The hottest player on the tour was Auger-Aliassime. He won all of his titles this year.
In the previous Davis Cup stage, he beat Carlos Alcaraz after the Spaniard had won the US Open. The Canadians started this week by beating Germany.
They are not kids anymore. "After the last couple of years, not after today," said Pospisil, the team veteran at 32. The people have been crushing it.