Lining up in 4-5-1 formation, they had battled their corner well only for a defensive lapse to let Saulius Mikoliunas in at the back post to grab an in jury time winner!
That was harsh justice on a United side that had no less than seven members of the current youth teams after Robbie Feeney replaced the injured Ross Gardiner after 38 minutes with Stuart Duff the only Tangerine with extensive first team experience.
By contrast, in addition to the Tynecastle matchwinner, Robbie Neilson, Roman Bednar and Calum Elliot all played the full ninety minutes.
Despite that, apart from a last ditch challenge by Neil McMechan preventing Matthew Park scoring on the stroke of half time, there were few scoring opportunities in the opening half.
In the second half, Barry Callaghan and Marco Andreoni went close for United with Bednar also having a chance sandwiched between those efforts from the visitors.
Five minutes from the end, United appeared to have won a penalty. Whether Andreoni was brought down was not an issue, but the ref after consulting his assistant gave a free-kick right on the edge of the box that came to nothing.
All the more consternation in the United camp, therefore at conceding that last gasp winner.
Dundee United: McLean, McMechan, O'Byrne, Gardiner (Feeney 38), Pope, Callaghan, McCord, Andreoni, Duff, Easton, J Russell.
Subs not used: Gibson, Mathieson, Jeffrey.