The Guelph Storm downed the Ottawa 67's 7-2 on Monday night to hand the 67's their first loss of the Ontario Hockey League playoffs.
Guelph's win in Game 3 of their OHL final series, cut the 67's lead to 2-1 in the best-of-seven set.
Ottawa had won 14 straight post-season matchups, including four-game sweeps of their opponents over the first three rounds.
MacKenzie Entwistle, Alexey Toropchenko and Isaac Ratcliffe scored two goals each to lead the Storm Monday night.
Sasha Chmelevski and Graeme Clark supplied the offence for Ottawa.
Guelph goaltender Anthony Popovich stopped 18 shots.
Cedrick Andree made 29 saves for the 67's, as Amherstburg native Mikey DiPietro is out with an ankle injury.