Mark Scheifele scored four times during Barrie's five-goal third period, as the Colts bounced the London Knights 6-4 in Game 4 of the Ontario Hockey League final on Wednesday.
The win puts Barrie a win away from its second-ever Memorial Cup appearance, as it takes a 3-1 series lead.
"It was a good third period for us," said Scheifele, whose Colts trailed 3-1 after 40 minutes. "We really put it together."
"In that second intermission, we said that we had to buckle down, take this opportunity, and it took a team effort to get that win."
Scheifele, who had three goals and two assists in Monday's victory, also picked up an assist, and has 39 points in 19 post-season contests.
Josh MacDonald and Anthony Camara also scored for Barrie, while Zach Hall had three assists.
Bo Horvat, Ryan Rupert, Tyler Ferry and Brett Welychka scored for London, which led 2-1 after the first period, and 3-1 after two.
Mathias Niederberger turned aside 29 shots for the Colts, while Knights goaltender Anthony Stolarz made 20 saves.
The Colts found some success on the power play, going 1-for-5. London finished the evening at 0-for-2.
Barrie scored 37 seconds into the opening period — two seconds later than it had in Monday's win — but London took control from there, outshooting the Colts 23-10 as Ferry, Horvat and Welychka struck in succession.
Scheifele's marker 44 seconds into the third period was followed by MacDonald's second of the post-season.
Rupert tipped home a shot to give London the lead again, but Scheifele evened things up by converting Hall's cross-ice pass.
"Tonight was a game of momentum," said Colts coach Dale Hawerchuk. "We really struggled in the first couple of periods, handling the pucks, moving our feet. We really got momentum in the third and tried to run with it."
Scheifele then gave the Colts their first lead of the game, when he beat Stolarz from a bad angle.
He took a long pass from Erik Bradford to score an empty-netter for his fourth goal of the game.
Knights coach Dale Hunter sounded off after the game, believing that the Colts were guilty of embellishment.
"Actually, we played very well," Hunter said. "We had a 3-1 lead, and the last six minutes or so of the second period, they started diving.
"Belleville warned us about it, that Scheifele, these guys, love to dive and draw penalties. [They got] three in a row and it changed the course of the game that way."
Game 5 is Friday night in London.