The Rangers opened the scoring early, with a powerplay goal by Mike Petizian within 90 seconds of the puck drop.
But things fell apart for the Rangers from that point on as Spitfires centre Wyatt Johnson tied things up with a short-handed marker at the 10:27 mark.
Then Daniel D’Amico notched Windsor’s second straight unassisted goal with just under four minutes to play in the first period.
Things went from bad to worse for the home side in the second period as Will Cuylie, Louka Henault, Johnston and Matthew Maggio all scored over the first 13 minutes for the Spitfires to put the game well out of reach for Kitchener.
Two minutes after Maggio found the back of the net, Simon Motew would answer for Kitchener, finishing out the scoring for the game.
Windsor netminder Matthias Onuska made 27 saves to record the win while Jackson Parsons made 20 saves but let in the Spitfires’ first four goals before being pulled for Pavel Cajan. He would make 21 saves but also gave up the final two goals.
The Spitfires now lead the best-of-seven series 2-1 as the two teams will meet at the Aud again on Thursday night.