Rabs began the Eurosport Engineering Sectional League Cup by fielding new signings Liam McVey (Auchinleck Talbot),Darren Miller (Ardrossan Winton Rovers), Chick Connolly (Cumnock) and Kevin Bradley (Pollok).
Rabs raced into a 5th minute lead when Kevin Bradley cut into the box before despatching the ball past keeper Quinn. It took Cumbernauld only four minutes to draw level when Gary Gibson ran through a non existent home defence to rifle a shot past Robertson.
In the 16th minute Diack headed a Bradley corner over the bar then a minute later Miller failed to connect with a Lindsay cross in front of goal. United looked dangerous going forward with Rabs fortunate to scramble a O'Halloran cross for a corner. In the 20th minute Rabs central defender Jordan Smith suffered a nasty cut to his head in a clash of heads and after lenghty treatment was helped off the park to be replaced by Kenny Connolly.
United's keeper Quinn took a Lindsay free-kick low down but the goal came at the other end in the 33rd minute when a McLaughlin cross found Jack Sloss who made no mistake with a decent effort. Six minutes later Rabs pulled themselves back on level terms when Ian Diack sent in an 18 yard shot past Quinn via the upright.
Half-Time; Rob Roy 2 v Cumbernauld United 2.
First chance of the second half fell to Rabs with Diack's back heeler going inches past, Then in 48th minute Paul McLaughlin took advantage of sloppy Rabs defending to slot the visitors in front. United could have added to their tally but O'Halloran hammered over the bar from an angle. Kenny Connolly limped off to be replaced by Murray.
In the 53rd minute a Murray strike cannoned of both posts it fell to Diack who fired the loose ball into the back of the net only to have it disallowed by the assistants flag for offside, then from a Lindsay short free-kick Coakley's 20 yard free-kick hit the post with Quinn beaten.
On the hour mark Rabs made their third change with Gormley coming on for Coakley. Rabs continued to attack with Murray heading over and Easton testing Quinn from the edge of the box. The hard working United side were giving little away and as the minutes ticked on it always looked unlikely that they would concede.
Full-Time; Rob Roy 2 v Cumbernauld United 3.
Verdict; A poor showing by the home side but take nothing away from Cumbernauld United once they took the lead for the second time they dug deep and still dangerous on the break and over the ninety minutes deserved their victory.
Ref Watch; Little to bother Referee William Wilson apart from a tousy ten minute spell in the first half. Always in control and let the game flow.