Jamie Mackie fired a stoppage-time winner to give Oxford a 1-0 victory over relegation rivals Bradford in controversial circumstances at a windswept Kassam Stadium.
Seconds after Bantams substitute Lewis O'Brien had shot wide at the far post from three yards on a rare counter-attack, Oxford found the net when Gavin Whyte's shot ballooned up and substitute Mackie superbly volleyed high into the goal.
But confusion reigned as Oxford's official Twitter account reported the goal was ruled out, with the referee seeming to award a penalty to Bradford before overruling that decision and giving Oxford the goal.
The U's finishing had previously been poor, with most shots off-target.
And when top scorer James Henry did eventually get his sights right from a 20-yard free-kick in the 63rd minute, keeper Richard O'Donnell saved well to his left.
City created few chances, one of their best coming when centre-half Anthony O'Connor saw his downward header at a corner 16 minutes from time bounce down and over the bar.
Bradford had to cope with the wind against them in the second half, which started with Whyte and then Jordan Graham again firing over but Mackie had the last word.