Samoa scored a last-gasp try to defeat Canada 21-20 and set up a Pacific Nations Cup final showdown with Fiji in Toronto.
The Samoans looked to be slipping to a surprise defeat after Canada's Sale Sharks wing Phil Mackenzie raced over for an opportunistic converted try to put the home side 20-16 up with four minutes left.
But Samoa punished a needlessly conceded penalty by setting up a line-out on Canada's goal-line with just seconds left.
And when Canada knocked on from the set-piece, Sakaria Taulafo was on hand to touch down for the winning score.
Canada had raced into a 13-0 lead through a try from centre Nick Blevins and eight points from the boot of full-back James Pritchard.
Samoa responded with a penalty from Michael Stanley to make it 13-3 at half-time.
The Samoans looked to have got a grip on the contest during the second half, scoring an early try through Anthony Perenise converted by Stanley.
Two more Stanley penalties gave Samoa a 16-13 lead before Mackenzie's late effort put Canada back in front until Taulafo's late winner.
Fiji hold off Japan
Earlier, Fiji withstood a furious late onslaught from Japan to book their place in the final with a 27-22 victory.
The Fijians finished a see-saw battle against the 2014 champions with two players in the sin-bin as Japan pressed desperately for a match-winning score that would have completed a remarkable comeback.
The Japanese had taken an early lead through three penalties from full-back Ayumu Goromaru before Fiji hit back with a devastating 10-minute spell.
Tevita Cavubati, Joshua Matavesi and Metuisela Talebula all crossed for converted scores as Fiji, who also scored a Matavesi penalty, transformed the contest to take a 24-9 lead at half-time.
But Japan came roaring back after the restart, with right wing Akihito Yamada scoring in the corner to make it 24-14.
Goromaru missed the conversion but slotted a further penalty to reduce Japan's deficit to 24-17 after 52 minutes.
Matavesi restored Fiji's 10-point cushion with his fifth successful kick of the day to make it 27-17 but Japan hit back once again through their powerful scrum.
A superb pick-and-go by New Zealand-born No 8 Hendrik Tui saw the back rower crash over from close range to make it 27-22, although Goromaru missed the conversion
In a frantic finale, Japan looked poised to claim the win as Fiji's composure deserted them. Second row Leone Nakarawa was sent to the sin-bin in the closing minutes and was then joined by loosehead Campese Ma'afu.
Despite the advantage, Japan were unable to find a way through and eventually conceded a penalty with the last kick of the game as an exhausted Fiji held on for a nervy win.
Earlier, Tonga, who were denied a place in Monday's final by Samoa's win, completed their group stage campaign with a 33-19 victory over the United States.