Cardiff won 4-1 in Belfast to remain as Group B leaders in the Elite League play-offs with a game remaining. The score was tied at 1-1 after 25 minutes, but the Devils pulled ahead with goals from Nathan Rempel, Phil Hill and John Craighead.
In Group A, top team Coventry lost their final game 5-4 in Nottingham, with David Clarke netting a hat-trick for the Panthers.
Their other scorers were Calle Carlsson and Konstantin Kalmikov.