Deadline day signing David Connolly scored on his debut to help
overcome AFC Wimbledon and move into the automatic promotion places.
Tom Newey nodded the hosts ahead from Danny Rose's corner before the break.
On-loan Portsmouth striker Connolly
made it 2-0 with a clipped finish after coming on as a second-half substitute.
Charlie Wyke pulled one back at the second attempt after Ryan Clarke saved, and Danny Hylton nearly levelled in stoppage time but headed wide.
Victory brought the U's back-to-back home wins for the first time in 18 months, while the Dons are still waiting for their first point against Oxford after eight attempts.
VIEW FROM THE DRESSING ROOM
AFC Wimbledon manager Neal Ardley told BBC London 94.9:
"It is disappointing in result terms and I didn't think there was a lot between the teams.
"We let ourselves down. They had one attempt on goal for the first half and that was their goal.
"I told them it is about both boxes and we were as good as, if not better, than them and we lost both boxes in the end."
Oxford United 01 Clarke 13 Hunt 03 Newey 22 Wroe 34 Bevans 19 Mullins 07 Rigg (Connolly - 46' ) 17 Rose 09 Constable (Kitson - 83' ) 10 Smalley 37 Ruffles Substitutes 08 Kitson 18 Davies 20 Marsh 23 Henly 24 Connolly 30 Long 35 O'Dowda AFC Wimbledon 01 Worner 02 Fuller 15 Fenlon (Sainte-Luce - 65' ) 28 Jones 27 Morris (Midson - 79' ) 06 Bennett 14 Antwi (Arthur - 64' ) 08 Moore 26 Wyke 09 Hylton 12 Pell Substitutes 07 Francomb 10 Midson 11 Moore 16 Sainte-Luce 18 Sheringham 19 Arthur 22 Brown
Ref: Andy D'Urso