The Varsity Reds, coached by Bedeque native Gardiner MacDougall, had already clinched first place in the very tough AUS conference.
Before 2,385 fans at the Aitken University Centre, the Panthers trailed 2-0 midway through the game before Jordan Mayer and Travis McIsaac scored 2:23 apart to tie the contest heading to the third.
Critchlow, who played minor hockey in Summerside, scored the game-winning goal 6:55 into the final frame.
Houde-Caron had two goals while Nick MacNeil and Montrose's Colby Pridham each had a goal and an assist. Pridham, whose 12th goal of the season at the 17-minute mark of the first period opened the game’s scoring, now has 30 points in 27 regular-season games.
Chris Desousa, Cole MacMillan and Reggie Traccitto had assists for the Panthers, who suffered their second loss of the weekend after dropping a 5-0 road decision to the Moncton Blue Eagles on Friday night.
Daniel Lacosta stopped 19 shots for the win while Wayne Savage made 34 saves in the loss. The conference-leading Varsity Reds improve to 22-5-09 (won-lost-overtime/shootout losses) while UPEI falls to 14-11-2.
UPEI closes out the regular season at home against the St. Thomas Tommies (3-22-1) on Friday at 7 p.m.