The London Knights put a stop to the Colts' 8-game winning streak.
Barrie also suffered their first loss at home on Saturday night.
Matt Rupert was the only player to score in the shootout as the Knights managed to squeak out a 3-2 victory at the Barrie Molson Centre.
After a scoreless first period, London took a 2-0 lead in the second on goals by Kyle Platzer and Josh Anderson.
The Colts replied early in the third as Anthony Camera and Aaron Ekblad scored to tie it up at 2.
There were a number of opportunities early in the game for the Colts but they were unable to score.
London's Alex Broadhurst and Barrie's Steven Byers each had two assists in the game.
Mathias Niederberger made 37 saves for the Colts.
Jake Patterson made his first start in goal for the Knights and turned away 26 shots.
The loss drops Barrie's record to 9-2-and-1 and they are back on the ice Sunday afternoon against the Battalion in Brampton.