A wonderful strike from Jim McIntyre five minutes from time rescued United and gave them their first victory of the season against a battling Caley side who will consider themselves unfortunate not to have taken something from the game After a lethargic 18 minutes the Tangerines came to life and it nearly produced the opener.
Mark Wilson's stunning inside ball found McIntyre who neatly laid the ball into the path of Jason Scotland. The Trinidadian's drilled shot was superbly tipped around the post by Mark Brown.
Caley were not there however to make up the numbers, fighting for every ball. As the game swung like a pendulum, only a great finger-tip save in the 25th minute from Tony Bullock prevented a certain opener from Barry Wilson as his 22-yard shot arrowed into the top corner.
Scotland almost got the hosts off to a perfect start after the break, running at pace past four defenders over 50 yards, but Brown was well positioned to hold his powerful strike.
Then three minutes later Billy Dodds, who was not having one of his better games, lofted over the bar when he just had the keeper to beat.
The pressure was increasingly towards Caley's goal. Debutant Grant Brebner, who had been influential throughout, fired just wide in the 59th minute with Brown beaten.
But the game became embroiled in fever pitch controversy in the 60th minute when the visitors were awarded a controversial penalty.
Ross Tokely passed in to space for Juanjo who appeared to dive as Bullock came out to collect the ball. After Wilson had slotted the ball away, Dodds was fortunate to be the only Tangerine to be cautioned for a vociferous reaction to the award.
Aggrieved, United struck back, but a miracle save from Brown in the 67th minute prevented a McIntyre goal.
Then Alan Archibald's volley struck his own player on the goal-line to prevent the equaliser. But the pressure finally paid off three minutes later when Chris Innes fired home.
After surviving a number of corners, Brown once again made a superb save from Dodds, but the rebound fell to the defender who slammed the ball in from eight yards The Terrors streamed forward in search of the elusive winner and they were finally rewarded in the 85th minute.
After a neat three-man move the ball was passed to McIntyre, who chested the ball down wheeled round and fired an unstoppable 20-yard shot past the despairing dive of Brown.