Hosts Oxford did all they could to ensure this afternoon's match went ahead - and their efforts proved worthwhile.
United came from behind in the second half to seal the points in what was a game of two halves.
It means Barnet remain in the relegation zone and are still searching for their first away win.
The Bees were the better team in the first half and went into the interval in full control.
Their goal came ten minutes before the break, Mark Marshall on target after good work by George Francomb and Kevin Gallen.
Wingers Marshall and Francomb were both giving their markers a torrid time and it was looking good for the visitors going into the second half.
But it was all change after the break. Oxford took control and hit back with two goals.
They equalised just after the hour mark in fortunate circumstances, Barnet's Anwar Uddin seeing the ball hit him and trickle over the line for an own goal.
The home side were now looking the likelier to find a winner and it came with seven minutes remaining, top scorer James Constable coming off the bench to do the honours.
After such a promising first half, it was a huge disappointment for Barnet.
It was their second consecutive defeat and the Bees will now have to attempt to bounce back next Saturday, when Accrington Stanley are the visitors to Underhill.
BARNET (4-4-2): Cole; Devera; Basey, Uddin, Parkes; Francomb (McLeod 75), Southam, Hughes (Jarvis 69), Marshall; Gallen (Holmes 60), Kabba. Subs not used: Coulton (GK), Cox, Vilhete, C Stimson.
Attendance: 6,004.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here