A stunning first period display put Braehead Clan on the road to two huge league points as well as a place in the Challenge Cup semi-finals.
Drew Bannister's men put Elite League leaders Belfast Giants to the sword in a stunning opening 20 minutes that saw them 3-0 up by the first interval.
Kyle Bruce opened the scoring after six minutes from close range after guiding the puck into the net from Matt Haywood's pass.
Former Giant Mike Bayrack, who left the Ulstermen in the summer, netted Clan's second.
Set up by Tim Wedderburn's scooped pass, the Canadian rampaged down the left before venomously striking the puck into Belfast netminder Stephen Murphy's far corner.
A sloppy pass by Jeff Mason followed allowing Jade Galbraith to add the home side's third, crossing the blue line and smashing into the net.
Despite outshooting the hosts by two to one after the break, Belfast only registered once on the scoresheet through Aaron Clarke a minute into period two.
Benoit Doucet and Nick Kuiper combined down the right, with Clarke on hand to send the puck beyond Clan goaltender Jaakko Suomalainen to offer some hope.
However, Bannister's men stayed strong and it was the player-coach himself who scored an empty net goal late in the third to seal a remarkable two points for the home side.
Afterwards Bannister said: "One of our goals at the start of the season was to qualify for the semis of the Challenge Cup. Now we've done that and I'm happy with the effort."
Scottish results and scorers:
Saturday 5 November
Elite League/Challenge Cup
Braehead Clan 4-1 Belfast Giants: (Bruce 6:10, Bayrack 16:37, Galbraith 18:24, Bannister 57:47 EN); (Clarke 20:57)
Edinburgh Capitals 3-8 Coventry Blaze: (Valecko 10:32, Menton 37:41, McKenzie 42:45); (Fussey 2:27, Neil 3:47, Farmer 16:11 PP, Neil 33:34, Kralj 35:58, Fussey 40:55 SH, Guthrie 48:00, Guthrie 54:46)
Fife Flyers 2-3 Dundee Stars: (McAlpine 35:17 PP, Hamilton 55:02); (McKenzie 0:44, Valecko 31:14, Jarolin 3:39 OT)
Sunday 6 November
Nottingham Panthers 3-2 (ASO) Fife Flyers: (Champagne 11:36, Francis 16:29); (Siddall 28:02 PP, Hartmanis 49:06)
Sheffield Steelers 6-1 Edinburgh Capitals: (Legue 3:56, Esders 14:56, Squires 23:29, Legue 34:11, Sarich 39:40, Clark 43:42); (Jarolin 16:05 PP)
Dundee Stars 2-2 Braehead Clan: (Ceman 1:17, Mitchell 12:18 PS); (Bayrack 14:06, McPherson 56:36)