Canada clinched their ticket to their second final, after 2019, by defeating Italy 2-1 in Saturday's second semi-final.
Felix Auger-Aliassime and Vasek Pospisil offered the point of victory against Matteo Berrettini and Fabio Fognini, beaten 7-6 (7/2), 7-5 in the decisive double.
Yet led 15-40 on his serve, Auger-Aliassime chained two aces and did not miss his chance on his first match point.
To discover
Davis Cup: Schedule and results
Lorenzo Sonego had however given the advantage to Italy by winning the first single against Denis Shapovalov 7-6 (7/4), 6-7 (5/7), 6-4, but Auger-Aliassime had brought back the two teams tied by beating Lorenzo Musetti 6-3, 6-4.
Australia, who beat Croatia 2-1 in the semi-final on Friday, are the second most successful team in Davis Cup history with 28 titles, but had not reached the final since their last crowning in 2003. Canada lost its previous final with Auger-Aliassime and Shapovalov already, in 2019 against Rafael Nadal's Spain.
Spain, deprived of Nadal and world No.1 Carlos Alcaraz, fell in the quarter-finals against Croatia.
The defending champion, Russia, is excluded from the competition due to the invasion of Ukraine.
The results of the second semi-final:
Canada defeats Italy 2 to 1
Lorenzo Sonego (ITA) defeats Denis Shapovalov (CAN) 7-6 (7/4), 6-7 (5/7), 6-4
Felix Auger-Aliassime (CAN) beats Lorenzo Musetti (ITA) 6-3, 6-4
Felix Auger-Aliassime/Vasek Pospisil (CAN) beat Matteo Berrettini/Fabio Fognini (ITA) 7-6 (7/2), 7-5