Justin Lemcke and Remi Elie had goals in regulation for lowly Belleville (7-18-4) as both teams combined for a four-goal second period.
Jimi Kuronen and Jacob Busch scored for Eastern Conference-leading Oshawa (21-7-2).
Bulls goaltender Charlie Graham made 36 saves and stopped both shooters in the shootout, while Ken Appleby stopped 42 shots for the Generals.
KNIGHTS 3 GREYHOUNDS 2
LONDON, Ont. — Anthony Stolarz made 43 saves as the Knights edged Sault Ste. Marie.
David Miller and Jared McCann replied for the Greyhounds (19-6-3).
Sault Ste. Marie goalie Matt Murray finished with 33 saves.
ATTACK 5 RANGERS 3
OWEN SOUNDS, Ont. — Jaden Lindo's two goals led the Attack past Kitchener.
Gemel Smith, Ethan Szypula and Holden Cook each scored for Owen Sound (14-10-5), which scored four unanswered goals for a 5-1 lead.
Mason Kohn, Nick Magyar and Ryan MacInnis had a goal apiece for the Rangers (10-16-1).
Brandon Hope stopped 37 shots for the Attack, while Rangers goalie Matthew Greenfield allowed all five goals on 32 shots.