A goal in each half from Tyrone Barnett and Alfie Potter earned Oxford a 2-0 win over Tranmere at the Kassam Stadium.
Matt Gill and Alex Russell named an unchanged starting line-up from the game against Plymouth, with Owain Fon Williams returning from international duty to be named among the substitutes.
George Barker had the first chance of the game inside two minutes. The striker, on loan from Swindon, intercepted a stray Oxford pass 25 yards from goal and spotted Ryan Clarke off his line but his attempted lob was caught by the keeper.
Michael Ihiekwe and Marcus Holness both prevented shots on Peter Brezovan's goal while Jason Koumas curled a 25 yard free kick over the bar on 17 minutes.
Kayode Odejayi stepped over a pass from Barker on 19 minutes, allowing the ball to run to Max Power whose first time right foot shot from 15 yards was kept away from the bottom left corner by the hand of Clarke.
Rovers broke up the left on 28 minutes but a cross from Danny Holmes was cleared and Oxford quickly launched a counter attack. Tareiq Holmes-Dennis found Danny Hylton on the right wing and he slid the ball into the area from where Tyrone Barnett turned into the bottom left corner to give the home side the lead.
Brezovan raced off his line to save from Barnett on 39 minutes and the keeper pulled off a fine one handed stop to keep out the striker's header in the first minute of added time.
Marc Laird replaced Gill at the start of the second half, the first substitution for either side.
A right foot shot from Barker was blocked on 58 minutes after the striker was found by Koumas and a Donnelly effort deflected wide of goal soon after.
The home side somehow failed to double their lead on 64 minutes. A ball across goal from Joe Riley found Hylton just a yard from goal but his shot hit the bar, bounced down on to the goal line and away from goal into the hands of Brezovan.
Abdulai Baggie and Eliot Richards replaced Odejayi and Barker with 20 minutes remaining but soon after Rovers found themselves two goals down. A right wing cross from Joe Riley was missed by Hylton on the edge of the six yard box but the ball reached substitute Alfie Potter ten yards out and he slammed a first time shot into the net at the back post.
Rovers searched for a way back into the game late on but couldn't produce a clear chance and went home empty handed.
Oxford: Clarke, Riley, Mullins, Wright, Holmes-Dennis, Collins (Ruffels 84), Whing, Hylton, Rose (Roberts 88), O'Dowda (Potter 64), Barnett. Substitutes: Long, Raynes, Morris, Meades.
Tranmere: Brezovan, Donacien, Holness, Ihiekwe, Holmes, Koumas, Gill (Laird 45HT), Power, Donnelly, Odejayi (Richards 71), Barker (Baggie 71). Substitutes: Fon Williams, Davies, Rowe, Kirby.
Referee: Kevin Johnson
Yellow cards: Donacien (41), Donnelly (56), Holmes (62)