Rochdale manager Steve Parkin praised the fitness of his side after they scored a last-minute winner to beat Oxford for the second week running.
Dale did it in the FA Cup seven days earlier, and this time they had fortune on their side when Tony Gallimore's 20-yard shot struck the post and went in off the back of keeper Chris Tardif.
Oxford had looked like holding on for a draw to boost caretaker manager Darren Patterson's hopes of landing the job full-time.
Oxford, though, had been very poor in the first half, and were luck to escape without conceding.
Dale's top scorer, Grant Holt, sliced horribly wide with a lob when he had just Tardif to beat.
Holt also missed with a header and then he curled a right-footed shot just wide midway though the second half.
Oxford failed to create any good chances and the closest they came was when Lee Bradbury headed over from Sam Togwell's right-wing cross.
But Oxford fans were delighted to see the return of Jamie Brooks, who came on for his first league game in two-and-a-half years. He had been sidelined with a life-threatening illness.
Brook's almost earned United a late penalty before Gallimore's drive earned Rochdale their third successive league victory, although the winning goal was being put down as a Tardif own goal.