Matt Keith gave Clan the lead, but Darian Dziurzynski scored twice to secure the points for Storm.
The Altrincham-based club followed up with a 3-1 Challenge Cup win at home to Coventry Blaze.
The Devils bounced back with a 6-1 home victory against Fife Flyers.
Pavel Vorobyev scored the overtime decider for the Capitals in their 3-2 cup win at home to the Clan, while Cale Tanaka (2) topped the scoring for the Stars in their 6-3 road success against the Flyers.
Cardiff Devils 6-1 Fife Flyers
Dundee Stars 3-5 Belfast Giants (Cup)
Edinburgh Capitals 3-2 Braehead Clan (OT) (Cup)
Manchester Storm 3-1 Coventry Blaze (Cup)
Sheffield Steelers 7-5 Nottingham Panthers (Cup)
(Image permission: Al Goold Photo)