Barnsley registered back-to-back victories with a fine performance on the road against the U's.
Goals in either half from Bobby Thomas and Nicky Cadden helped the Reds to another big three points in Sky Bet League One.
Whether the enforced rest following the postponement of our last fixture helped energy levels or not, Michael Duff's men were first to every ball in the opening quarter of this one.
Despite a bright and dominant-looking start in Oxford, it was our hosts who had the first opportunity on the night. A long ball over the top saw the Reds backline claiming offside, hands in the air, allowing seven-goal striker Billy Bodin to run in towards goal but the U's forward screwed his effort a foot wide.
That seemed to fire up an already imposing Reds side. There were moments of real quality in the building of moves, in and around the U's box. But the clear-cut chances weren't appearing.
One exciting move saw James Norwood in off the shoulder of the defender but the striker's low shot from 14 yards was blocked on the line by a retreating Oxford defender.
A little period of frustration seemed to interrupt Barnsley. The game became stop/start with United midfielder Cameron Brannagan three times falling to the turf in pain. He was eventually replaced just after 20 minutes by Marcus McGuane.
The home side then forced a handful of corners and long throws, but Duff's side repelled the pressure nicely, looking to reassert their own control.
That control came on the half-hour mark as an inviting Adam Phillips left-footed cross from the right flank was glanced into the top corner by Bobby Thomas; the on-loan defender's header putting us ahead.
Another ball over the top from Oxford came as a further warning to Barnsley, as Kyle Joseph beat Liam Kitching before firing a powerful strike well wide from 10 yards out.
As we headed towards the half-time whistle, Luca Connell - imperious in midfield in the opening 45 - skipped into a positive position wide left of the box and his cross/cum shot arrowed just a foot wide of goal.
HALF TIME: Oxford United 0-1 Barnsley
The Reds were close to a second goal early in the second period when Kitching's low cross from the left, fired in at pace found Phillips but the midfielder, arriving at speed couldn't set himself adequately and his stabbed shot at the near post cleared the bar.
Proceedings became untidy as the hosts resorted to direct football, looking long at every opportunity.
Just before the hour was up, Barnsley doubled their lead at the Kassam Stadium, and another fresh goalscorer.
Great stuff from Norwood on halfway, he brilliantly held up the ball with two men trying to thwart him, before playing Devante Cole in down the right and after a couple of attempts, the number 44 found Herbie Kane on the penalty spot with his cut-back, and unselfishly, Herbie laid off perfectly for the arriving Nicky Cadden who stroked home into the bottom corner. His first Reds goal, and crucial.
Norwood could have made it three soon afterwards when Phillips poked a ball through for him towards the edge of the box, but James' low shot was expertly saved with his left foot by goalkeeper Simon Eastwood.
The hosts' barrage of long balls only increased as time went on, as did their propensity to use set-plays. It paid off when a Bodin corner picked out an unmarked Elliot Moore central inside the box and his downward header beat Brad Collins and into the far corner to reduce the arrears.
Pressure was ramping up at this point, and Ciaron Brown's acrobatic strike from another Bodin outswinging corner hit the top of Collins' crossbar.
The Reds wrestled back control in the final stages, and despite a bizarre eight minutes of time added on, Duff's Reds were canny in managing those dying embers to record an impressive victory and stick another three points on the board.
FULL TIME: Oxford United 1-2 Barnsley
Collins, Williams, B.Thomas, Andersen, Kitching, Cadden, Kane, Connell, Phillips, Norwood (Martin), Cole (Watters).
Unused: Isted, Oduor, Pache, Larkeche, Shaw.