United put then their visitors under more pressure in the first half hour and increasing the lead looked likely.
AFC Mansfield striker Guiseppe Iaciofano, on loan from Northampton, had other ideas though and he struck a hat-trick in an amazing six minute spell.
In the 29th minute he converted a penalty after the referee controversially judged a challenge in the United box as a foul. Then the lively away striker converted two more close-range chances in the 32nd and 34th minutes.
A stunned Whites team tried to regroup and tighten up at the back, while looking to get the goal that would get them back into the game. It wasn't to be however, with few chances being created up to the break or in the whole of the second half.
Johno Williams came closest with a shot blocked by the Bulls keeper's legs, but there was no further change to the score-line.
United dropped to seventh in the table following this latest set-back and manager Sam Wilkinson will be looking hard for the changes he might need to make to get his side winning again.