With six minutes to go United were cruising 4-1 ahead but lost two preventable goals in the last minutes to leave the home support and coach George Shaw on tenterhooks.
United, with several regulars missing, fielded two new players on loan from Airdrie, John Higgins and Murray Loudon. Goalkeeping coach Ian Wilson also had to come out of retirement to play.
The visitors made a strong start but the home team soon settled and from a Davie Dickson corner their trialist central defender hit the bar with a header.
United’s Billy Robb was fortunate to escape a red card for a bad tackle on Vics’ Jordan Craig who had to be substituted. Wilson then made a great save with his feet to prevent Callum Davidson putting the Ayrshire team ahead.
However United took the lead on 40 minutes when, from an excellent Higgins cross, Ross Foley controlled the ball well to score a great goal.
Following the break the home team continued to dominate and skipper Ryan Sullivan came near with a fine shot well saved.
Against the run of play however Irvine were awarded a penalty on the hour and striker Kevin Adam did the necessary.
Within a minute United regained the lead when a terrific Foley-Dickson move gave Loudon an opening to score.
Two minutes later Cumbernauld added to their lead when Loudon put Simon Eeles in the clear and the experienced winger beat Chris Lamb in the opposing goal.
United’ support had hardly time to draw their breath when their favourites got a fourth goal,
A clearance from Wilson found Eeles who crossed for Loudon to score his second goal on his debut.
It looked all over but the visitors pulled two goals back in the closing minutes through Carlo Scaramuzzo and a Dickson own goal to leave United hanging on to their lead.