How the Tannadice teenagers managed to lose this match beggars belief.
Having established a 3-1 advantage early in the second half, it only looked a question of how many as they threatened to run up a cricket score.
Unfortunately, some fragility in defence allowed the visitors to stage an unlikely comeback and plunder a last minute winner.
There were portents of things to come when Hamilton took the lead due to slackness in the home defence midway through the first half.
Home keeper Brynn Hindley was forced into giving away a penalty after Euan Lindsay capitalised on a stray pass and David Hopkirk sunk the spot-kick.
Within five minutes United were on level terms, Dale Hilson firing home from the corner of the box.
Then on the stroke of half-time Stuart Armstrong side-stepped a defender to put the hosts ahead with a well-struck low right foot drive from just outside the box.
United emerged at the start of the second half with all guns blazing and could easily have scored three times before Ryan Dow netted a third with an angled finish from twelve yards after latching on to a misplaced pass.
However, Chris Roxburgh pulled one back with just over 20 minutes left and as United continued to pass up chance after chance to kill the game, the nerves set in at the back..
Indeed, it almost came as no surprise when an unmarked Jordan McCur equalised from Gerald O'Connell's cross with two minutes to go.
Almost immediately Michael Lee contrived to miss an open goal to put United back in front and completing a bizarre contest, Hopkirk's second of the afternoon in stoppage time earned Accies an incredible three points.
Dundee United: Hindley, Irvine, Mosson, Hill, Shaw, Lee, Scott, Allan (L Swanson 61), Hilson, Armstrong, Dow (Thomson 89). Subs not used: McCallum, W Robertson, McCullie, Murray.