Morgan Ellis had an empty-net goal with four seconds to play to seal the victory for the Bulldogs (34-28-12), who sit three points back of the Toronto Marlies for the final playoff spot in the Western Conference with two games to play.
Brandon McNally, Charles Hudon, and Drayson Bowman also scored for Hamilton while Mike Condon made 23 saves.
Kyle Platzer scored twice for Oklahoma City (39-27-8), Brad Hunt added the other Barons goal and Laurent Brossoit stopped 16-of-20 shots. Steve Pinizzotto was given a game misconduct 5:28 into the game for physical abuse of an official.