Two second-half tries from Romanian captain Mihai Macovei led a remarkable comeback, which saw his side overturn a 15-0 deficit, to beat Canada 17-15 at the Leicester City Stadium.
The game looked destined to be a Canadian win after building a hefty lead off the back of two well-worked tries in either half.
It is Romania's first World Cup win in eight years after failing to win a game at the 2011 tournament, with a stunned Canadian side sent home with four straight defeats.
Van der Merwe scores again as Canucks build first half lead
The first half was all Canada, with an 8-0 lead at the break probably doing them a diservice.
A Gordon McRorie try gave Kieran Crowley's side the early lead after a number of strong breaks from their attack-minded backline. Canada winger DTH van der Merwe then did what he does best, scoring a try for the fourth straight pool game at this World Cup, following on from Shane Williams who did likewise in the 2007 tournament.
The Scarlets winger can certainly leave the tournament with his head held up despite the four defeats, and is bound to be in the conversation when it comes to picking the best team of the tournament after his expliots in the four matches.
Macovei leads from front to force epic victory
The second half started as the first half had finished with Canada well on top, and they made their dominance count with a second try scored by Jeff Hassler who broke a number of tackles to corss the line.
Hassler's try was converted by Nathan Hirayama to give Canada a 15-point lead which looked to be enough, before the astonishing Romanian fightback.
Just before the hour mark, Macovei got his side back in the game after being on the back of an excellent driving maul to reduce the arrears to just eight points following Florin Vlaicu's conversion.
As the game hit the last ten minutes the game was in the balance with Romania looking the more likely to score, and their chance arose when Jebb Sinclair was sent to the sin-bin after collapsing a maul close to his own line.
From the resulting penalty, Macovei picked up from the back of a dominant scrum to smash his way through a tackle and over the line for his second try, which was again converted by Vlaicu.
With a point deficit going into the last two minutes, a huge defensive effort forced a kickable penalty on the Canadian 10 metre line, which Vlaicu sent straight down the middle to cause scenes of delerium from the Romanian fans.
For Canada, this is a huge blow after seeing their hopes of a win ripped from them by in-discipline, but for Romania this victory will live long in the memory, and they take the momentum with them towards their last game against Italy on Sunday.