The devastating Diamonds terrorised Tannadice as Gabby McGill and Josh O’Connor got the goals in a superb 2-0 win over league leaders Dundee United.

Having lost to Ayr United and Greenock Morton in recent weeks, Airdrie were perhaps not expected to take anything from Jim Goodwin’s table-toppers, but Rhys McCabe has shown time and again that his side should never be underestimated.

There were a number of changes in the Diamonds ranks following Saturday’s disappointment at Cappielow, with Aaron Taylor-Sinclair, Dean McMaster, Nikolay Todorov, and Arron Lyall making way for player-boss McCabe, Liam McStravick, Calum Gallagher and McGill.

Former Airdrie striker Tony Watt led the line for the home side, though fellow ex-Diamonds Ross Docherty and Declan Glass missed out.

Dundee United were first to threaten as they pressed Josh Rae’s box after four minutes, but Mason Hancock, Callum Fordyce and McCabe all stood strong and made important blocks.

McCabe proved influential at both ends throughout the evening, and the midfielder had the Diamonds’ first attempt on nine minutes, launching an effort over the bar after good work from Liam McStravick.

Calm defending saw off the hosts again a minute later, with Alex Greive’s direct running ultimately coming to nothing.

Jack Walton beat McGill to a 15th-minute long pass from McCabe, and things took a worrying turn for the Diamonds seven minutes later when Hancock pulled up unopposed and limped off to be replaced by Craig Watson.

McGill saw another effort charged down as Airdrie threatened midway through the half, with Kanayo Megwa’s crossed being hustled away from Charlie Telfer who then found Fordyce with the corner kick, only to see Walton make a smart stop from the defender’s low strike.

Another Telfer corner had Airdrie asking questions as the ball seemed to strike a hand at the near post, but referee Grant Irvine waved away the claims.

Watson was the last line of defence as Greive broke away on 27 minutes, thumping clear just as the midfielder looked to have created space for a shot.

Good defending from Scott McMann foiled a combined attack from McGill and Gallagher just after the half-hour mark, with a powerful McCabe effort scrambled behind after a good headed block by Kevin Holt.

Dundee United’s best opportunity came from a 36th-minute Glenn Middleton setpiece, with the former Rangers man smashing his free-kick against the crossbar.

Rae was out his box quickly to clear a minute later, before McStravick and Cammy Ballantyne almost carved out an opportunity at the other end.

Watson denied Middleton a route to goal on 40-minutes, with Walton saving McStravick’s strike as play flowed from end to end.

Middleton found space after a quick throw two minutes before the break, but the midfielder fired wide and the sides went in goalless after an entertaining first half.

Dundee United started the second half strongly, with Watt missing the target when it seemed easier to score a minute after the restart.

As Airdrie began to regain control of the match, Scotland defender Declan Gallagher denied namesake Calum with a superb last-ditch block on 55 minutes.

Telfer and McStravick were pressing well in support of the Airdrie attack, and as the wide midfielders pulled the home defence out of position, it looked like a goal may be coming for the Diamonds.

Sure enough, on the hour-mark a neat passing move bore fruit, McStravick teeing McCabe up for a backheel pass to former United man Telfer, whose magnificent cross was equalled only by McGill’s headed finish which bulleted past Walton into the top corner.

The introduction of experienced campaigners Liam Grimshaw and Louis Moult did nothing to stem Airdrie’s dominance of the match, and Megwa saw a 64th-minute cross blocked behind before McGill rose highest again two minutes later, but this time the Yorkshireman nodded over the bar.

Moult’s header was easily held by Rae on 67 minutes, and further substitutions broke up play as Airdrie prepared for a late siege.

Declan Gallagher headed wide as the home side pushed men forward in the last 15 minutes, and Ballantyne and Fordyce slid in to block superbly as the home fans screamed in vain for a penalty.

Airdrie made a triple-substitution with nine minutes of regulation time remaining, with Todorov, McMaster and Josh O’Connor replacing Gallagher, McCabe and McGill, and it proved to be a fruitful change for the Diamonds.

Rae was in commanding mood as the Tangerines threw late crosses into the box, and two of Airdrie’s late subs combined to put the icing on the cake four minutes into stoppage time, Todorov hooking a Ballantyne clearance over his head to set O’Connor haring toward goal. Despite Grimshaw’s best efforts, there was no catching the on-loan Hibs striker, who drew Walton before calmly slotting between the keeper’s legs.

The final whistle sparked jubilant scenes among the Diamonds players and the vocal support who had made the journey to Tannadice, and a happy trip home was guaranteed for all before the hard work starts again ahead of Saturday’s home tie against Queen’s Park.