Ruben Rafkin's power-play winner came early in the second period of Windsor's rout of the Petes.
Luke Boka, Kyle McDonald, Cole Purboo, Connor Corcoran, Egor Afanasyev and Curtis Douglas also scored for the Spitfires (30-15-5).
Zach Gallant scored twice for Peterborough (31-20-3), while J.R. Avon chipped in.
The win pushed the Spits to within one point of fourth-place Flint in the Western Conference Standings and Windsor has a game in hand.
The Spitfires play in Kingston on Friday night, with AM800's coverage starting at 6:45pm with Manny Paiva's pregame show.