Rugby Park staged a veritable game of two halves tonight as Kilmarnock fought their way back from three down, only for the Tangerines to grab a late winner.
Blair Spittal set the tone after 14 minutes firing in a shot which warmed the hands of keeper Conor Brenan as he palmed it away.
But a goal was only delayed by a couple of minutes. Jordan Moore’s shot was beaten away by the keeper and Ali Coote, on his return from injury, squeezed the rebound into the bottom corner from 12 yards.
And Spittal doubled the visitors’ advantage on 18 minutes, drilling a shot low past the keeper.
Only a great save by Brennan prevented Scott Lochhead making it three midway through the half, but Coote did nine minutes from the interval with a shot just inside the near post.
With Saturday’s Youth Cup tie with Celtic in mind, Coach Stevie Campbell made two substitutions at the interval, Jamie Montgomery and Reghan Tumilty replacing Robson and Coote.
Having looked dead and buried at the break, the hosts suddenly came to life.
Just before the hour mark, Dylan Pooler ran on to a through ball to steer the ball past Luis Zwick.
Five minutes later, Pooler Further reduced the leeway, side-footing home a Dean Hawkshaw cross.
And Pooler completed the comeback and his hat-trick with eight minutes left.
However, United had the last word, Ola Adeyemo heading home from close range with two minutes left!
Dundee United: Zwick, Spark, Robson (Montgomery 46), B Smith, McLaughlin, Souttar, Adeyemo, Lochhead, Moore (Malaga 76), Spittal, Coote (Tumilty 46).
Subs not used: Booth, McNaughton, M Smith, Duke.