A deep ball to the back post was headed back across the box by Sean Dickson into the path of McGuigan who supplied the finish and earn a vital win.
It was McGuigan that looked the most likely to grab a goal for Stenhousemuir in the games’ early exchanges. He came close when he got on the end of a Conner Duthie corner, McGuigan’s header wasn’t met with the right contact and the ball went sailing over the bar.
The visitors' best chance fell to Alan Cook. McGuigan played Cook through on goal with only the goalkeeper to beat. Cook lobbed the ball over the head of the onrushing David Hutton but the ball fell just wide of the post.
As the first half came to a close Stenny had goalkeeper Graeme Smith to thank for keeping the game the level. Smith dived out bravely to the feet of Dale Carrick to turn the ball round for a corner.
Smith dusted himself off after some treatment and from the resulting corner, Smith pulled off a great save to deny Sean Crighton who came close to breaking the deadlock with a towering header.
Chances were at a premium in the second half, much like the first. A speculative effort from Alan Cook came close to opening the scoring. Cook hit a powerful drive from 25 yards out and Hutton had to be at full stretch to tip the ball round the post.
With little over 10 minutes to go the host’s thought they had nicked the points but Stenhousemuir were saved by the assistant referee’s flag.
Kyle Wilkie headed home a Joao Victoria cross but Airdrie's celebrations were short lived as the goal was ruled out for offside.
Then when time was running out McGuigan popped up to net the only goal of the game and pick up a vital three points for Brown Ferguson’s team.
It was a necessary win too with Dumbarton and Montrose both winning. Anything else than a win would have seen Stenhousemuir drop to the foot of the table.
As it is, Stenhousemuir move on to 12 points and stay in eighth place a point ahead of both Dumbarton and Montrose.