Dundee United player-manager Craig Brewster's return to Inverness ended in disappointment thanks to Craig Dargo's injury-time winner for Caley Thistle.
Both teams created little in disappointing game, with Charlie Mulgrew's early free-kick the closest the visitors came to scoring.
But the Highlanders struck two minutes into injury time when poor play from Alan Archibald allowed Dargo the chance to send an angled shot past Craig Samson.
A pedestrian start hampered by a strong wind swirling around the stadium yielded little enterprising football, until Mulgrew bent a sixth-minute free-kick just past Inverness goalkeeper Mark Brown's right-hand post.
Caley eventually mustered a shot on goal in the 18th minute when Liam Keogh's chip across the pitch found Hart lurking on the edge of the penalty area and the midfielder's controlled shot produced a fine save from Samson.
After a foul by David Robertson on Stuart Golabek tight against the touchline, Hart was then able to find the unmarked Keogh with a free-kick and the ex-Celtic youngster tried his luck with a shot from 25 yards.
The drive was flying well off course until the intervention of Ross Tokely, who sent the ball up into the air allowing Darren Dods a header at goal.
The central defender's effort eventually landed just past the post, but the alert Dargo was unlucky not to turn the ball into the net with a despairing lunge right on the goal-line.
In the 52nd minute, the former Kilmarnock striker was able to send a shot towards goal from Hart's corner, but, fortunately for the visitors, Mulgrew was stationed at the back post and, at the second attempt, cleared the ball off the line.
Dargo then became the architect for Inverness with a clipped pass which picked out Wilson on the edge of the six yard box, but the midfielder wanted an extra touch when he should have shot and Mulgrew was on hand to make a goal-saving challenge.
The on-loan Celtic player was at the heart of the action for United and, from his cross, Robertson was able to direct a header at goal which may have troubled Brown had it not been for the intervention of Dods who made an important block.
Inverness responded with a shot from Wyness from 18 yards which curled just wide, before Wilson's inswinging cross curled right across the face of goal when the merest of touches would have sent the ball into the net.
Seven minutes later, Brown made a good save from Mulgrew's free-kick, before Dargo capitalised on poor play from Archibald two minutes into stoppage time to score the winner with the last kick of the match.
Teams:
Inverness CT Brown, Tokely, Dods, Hastings, Golabek, Wilson,Hart, Keogh, McBain (Morgan 64), Dargo, Wyness (McAllister 81).
Subs Not Used: Fraser, McCaffrey, Bayne, Parratt, Sutherland.
Booked: Tokely.
Goals: Dargo 90.
Dundee Utd Samson, McCracken, Archibald, Ritchie, Gardiner,Duff, Kerr, Brebner (Abbot 85), Mulgrew, Samuel,Robertson (Goodwillie 75).
Subs Not Used: McLean, Kenneth, Cameron, Callaghan, Easton.
Booked: Kerr, Ritchie.
Att: 3,609
Ref: M Tumilty (Scotland).