Evan Bouchard's goal early in the second period stood as the winner as the Knights topped the Spitifres 3-1 in London.
Alex Formenton and Liam Foudy also scored for the Knights (32-21-4).
Luke Boka had the only goal for the Spitfires (26-25-5).
The 8th seeded Spits stay three points back of Guelph in the Conference standings.
The Spits host the 67's Thursday night, top ranked Sault Ste Marie is here Saturday and the Erie Otters will be in Sunday afternoon.