Miles Liberati scored the only goal of the first period to give the Knights a 1-0 lead.
The Knights increased their lead to 3-0 in the third period on goals by Bo Horvat and Owen MacDonald.
Connor Crisp scored the lone goal of the game for the Otters shorthanded as he streaked through the right wing and ripped a shot from the circle through Stolarz for his 22nd goal of the season at 10:38.
The Otters had plenty of chances to draw closer in the third, but Stolarz made 11 saves in the final 20 minutes to help the Knights earn the victory.
Next up for the Otters is a home-and-home series against the Guelph Storm that begins in Guelph Friday night at 7:30 p.m. Fans can listen to the action on Jet Radio 1400.
Locastro-Bonini Insurance Three Stars
No. 1 Star - Anthony Stolarz, London - 29 saves
No. 2 Star - Josh Anderson, London - two assists
No. 3 Star - Connor Crisp, Erie - one goal