Glenavon missed the opportunity to join Linfield at the top of the table after falling at home to Ballinamallard on Friday night.
It was a stormy night at Mourneview and not just due to the weather with Glenavon furious at the end when referee Arnold Hunter awarded the winning goal with players and officials saying the ball had not crossed the line.
The evening had all started so well for the Blues with Kyle Neill scoring direct from a corner kick on four minutes.
The home side had many other chances, including a Gary Hamilton chip which landed on top of the bar, to seal the points in the first half.
The failure to kill off United gave the visitors the chance to get back into the game as they played with the strong wind in the second half.
The equaliser came from a corner and in a scramble the ball was driven home by Ryan Campbell. To their credit Glenavon responded and a brilliant header from William Murphy restored the lead.
However, Ballinamallard battled back and Cathal Beacom made it 2-2 when he fired a free kick through the wall and past John Connolly.
Just when it looked like the spoils would be shared United grabbed all three points. A corner was swung in, Connolly appeared to be pushed over as he tried to collect and during the frantic melee in the box it did appear the ref blew his whistle before the ball was finally forced in by Crawford.
An unhappy and disappointing end to what could have been a rewarding night for Glenavon who will have to put this set-back behind them and look ahead to the next game against Ards.