Both sides had already booked their places in the Quarter-finals, but with a perfect record at stake and first place on offer, there was plenty for Canada to play for, while Finland were out to give themselves a chance of finishing in the top two and build momentum after a slow start to the championship.
The Canadians' squad, made up entirely of National Hockey League (NHL) players, has been too much for anyone else in the group to contend with so far.
But the Leijonat, with plenty of star power of their own, cancelled out the North Americans in a goalless first period which saw Canada shade the shot-on-target count, 11-10.
The midpoint of the match came and went and still neither side could find a way past goaltenders Juuse Saros and Marc-Andre Fleury, until one lapse in focus resulted in the opening goal with two minutes remaining.
Finland were looking to take advantage of a powerplay after Mackenzie Weegar was given two minutes for tripping, but a miscontrol inside the attacking zone from Harri Pesonen allowed Noah Dobson to race away and set up Nashville Predators' Ryan O'Reilly to score the shorthanded goal.
One goal was beginning to look like enough for Canada as Antti Pennanen's side were struggling to break through early in the third period, only registering two shots on goal in the first seven minutes.
However, two turned out to be plenty - from just inside the blue line on the right wing, Nikolas Matinpalo hammered a shot-pass into the danger area, which Patrik Puistola controlled with his stick before turning an firing past Fleury.
Both sides had chances to win it late on, but after 60 pulsating minutes, the two teams could not be separated and the match headed for overtime.
Nathan MacKinnon and Dobson had chances to deliver the decisive blow in the extra five minutes, but twice they were denied by Jaros, who finished with 37 saves. Finland came closest to a winner when Eeli Tolvanen played the puck across to Mikko Lehtonen, but he mishit his strike with the goal gaping, thus a shootout was needed.
Puistola scored Finland's first penalty, before Kent Johnson scored past Saros with Canada's second effort, only for Tolvanen to respond by rifling the puck into the top corner with Finland's third effort.
None of the next four penalties were scored, meaning Adam Fantilli had to score with Canada's fifth and final attempt. However, there was no way past Jaros, and Finland took the shootout victory.
Finland can now finish no lower than third in the group, but can still take second if they beat top four-chasing Slovakia tomorrow, and Canada lose to Sweden as they face off for top spot.
Earlier today in Group A, Slovenia were victorious in a winner-takes-all clash with France to remain in the Championship division and relegate France to Division 1A for the 2026 World Championship.
Goals from Zan Jazovsek and Nik Simsic put Slovenia in control in the first period, and though Tim Bozon gave the French a glimmer of hope in the final two minutes, Matic Torok sealed the 3-1 win with an empty-netter, as Slovenia finish on four points, three clear of France.
It ends France's four-year stay in the top tier, while the Lynx have survived an immediate return to the second tier for the first time in 20 years.
In Group B, Czech Republic returned to the summit by coasting to a 5-0 win over Germany, who are now at risk of not progressing to the Quarter-finals.
David Pastrnak scored his fifth goal and 12th point of the competition to open the scoring in the first period, before two goals from Jabub Flek and one apiece for Lukas Sedlak and Jakub Lauko in the following 40 minutes made for another routine victory for the unbeaten Czechs.
A goal difference of -1 means Germany slip below Denmark and into fifth in the table before the sides meet in their final group match tomorrow. Whereas the Danes have won three on the bounce having begun with three consecutive defeats, Germany have the opposite record - losing their last three.
Meanwhile, a first win of the World Championship for Norway has guaranteed their survival. They beat Hungary 1-0 in both sides' final matches to move from eighth to sixth in the group.
Noah Steen's goal in the seventh minute turned out to be the winner for Norway, who finish on four points, one clear of the Hungarians and Kazakhstan, leaving the Kazakhs needed something against Switzerland to send Hungary down in their stead.
Follow tomorrow's final day of World Championship group matches on Flashscore.