Gary Waddock made four changes from Saturday's starting eleven at York.
Danny Hylton replaced Jonny Dixon who had been signed by Brighton earlier in the day, subject to passing a medical.
In defence Rob Gier and Anthony Charles came in for Smith and Day respectively.
Joel Grant started out wide left, instead of Davies, which meant Harding moved inside to central midfield.
The Shots were fortunate in the first minute as the visitors flew out of the traps.
Recent signing from Kidderminster, Justin Richards, cut inside Rob Gier who mistimed his challenge in the area and appeared to bring down the former Woking forward.
However referee Mr Halliday turned away the furious protestations from the visitors.
Shortly after Joel Grant went on a jinking run leaving two defenders in his wake, and he put in a floated cross to the far post.
It was met by the head of John Grant, but his goal bound effort was well blocked.
At the other end Phil Trainer turned Gier inside out before firing his effort wide of the near post.
In the 7th minute a neat through ball from Joel Grant sent his namesake John clear of the Oxford defence, but on this occasion a weak finish followed.
Richards then fizzed an effort from 20 yards narrowly over.
Louis Soares' fierce strike from outside the box was directed straight at Turley, who spilled the effort, but quickly smothered the loose ball.
The Shots produced a flowing move down their left in the 24th minute, involving Joel Grant and Soares. The latter put a precise cross over for John Grant, but he didn't connect properly with his header.
The Shots wasted a number of good positions from set pieces with poor deliveries as the half rather fizzled out.
Half Time: Shots 0 - Oxford 0
In the 47th minute the Shots came close to breaking the deadlock. A defence splitting pass from Harding found Hylton, whose first time effort flashed agonisingly wide of the upright.
After a silky run Harding's pass found John Grant on the edge of the box.
The Shots leading scorer, after making himself room, got a decent effort in but it was directed straight at the keeper.
The defining moment came in the 65th minute. A poor back pass was fumbled behind for a corner by Turley.
The resulting Soares corner found John Grant remarkably unmarked in the 6 yard box and this time he planted his header firmly past the static keeper.
Davies then replaced Gier, who had earlier taken a knock, and Soares filled in at full back.
The substitute was soon in the action when he put over a decent corner. It was headed down and fell to John Grant, whose audacious back flick struck the base of the post.
The Shots were playing some flowing football now and Joel Grant mesmerised his full back with a couple of stepovers, before chipping it back into the area. It looked like it was going to fall perfectly for Ben Harding on the volley, but a team mate appeared to get in the way and he failed to make contact.
In the 77th minute Oxford substitute Yemi flashed the ball right across the 6 yard box , but it evaded all the yellow shirts.
Danny Hylton, who was a constant thorn in the side of the Oxford defence, and deserved his Man of the Match award, hit a well struck shot, which Turley saved well at the second attempt.
The visitors came close to an equaliser in the dying minutes, but a 25 yard thunderbolt from Matt Day cannoned back off the bar.
The Shots held firm for the remaining time to gain a much needed three points.
Bull 6, Gier 6 (Davies 6), Straker 6, Winfield 7, Charles 7, Chalmers 7, Soares 6, Harding 7, John Grant 6.5, Hylton 7.5, Joel Grant 7.
With thanks to Tongham Shots.