Defensive errors cost the young Tangerines what would have been a deserved share of the points in yesterday afternoon's league clash at St Andrews.
In an evenly, if at times frenetic affair, United keeper Marc McCallum suffered the agony of letting a David Chalmers well-struck 20-yarder slip through his hands for the visitors' last gasp winner.
The Tannadice side went took the lead after only two minutes.
William Robertson's corner was headed down by Shane Campbell to the unmarked Lewis Swanson whose shot from just inside the area was diverted home by Michael Lee.
The visitors leveller four minutes from the break followed a slip by United defender John Young which allowed Callum Dingwall through to score with a right foot shot into the bottom corner from the edge of the box.
But before the break, United were denied a stonewall penalty when Liam Scott was clearly impeded in the box.
Even more galling for the home side, the Highland youngsters then went ahead on the hour mark, Andy MacCaskill powering in a header from Chalmers cross from the left.
But United never gave up and were rewarded 12 minutes from time when Grant Mosson, taking a short free-kick from, rifled home the equaliser from 22-yards.
However, those efforts were then undone by man of the match Chalmers' winner with effectively the last kick of the game.
Dundee United: McCallum, Lee (Barratt 65), Mosson, Young, Shaw, W Robertson, Scott (Hawe 67), Stokes, Elfverson, Campbell, L Swanson (R Thomson 65). Subs not used: Ritchie, Ferguson).