Robbie Nielson’s MK Dons side have one win to their name in the league but beat Brighton's youngsters in the Checkatrade Trophy in midweek.
He said: “We have to get into the winning mentality but we haven’t done that this season.
“We used (Tuesday) as an opportunity to build some momentum going into our game on Saturday" Nielson said. “We decided to go semi-strong and put a few of the first team out there to give them a bit more game time and thankfully it worked.
“We need to bring that confidence to our league play and hopefully tonight helped with that.”
“Oxford got a really good result at Stevenage, so we know they’ll be coming here looking to get another win because they’ve made a good start to the season.”
Neilson's squad was bolstered by the deadline-day additions of defender Scott Golbourne, midfielder Alex Gilbey and winger Aidan Nesbitt.
Neilson will assess his injured players on Friday, with Osman Sow, Joe Walsh, Kieran Agard and Chuks Aneke all missing the league defeat at Blackburn while Peter Pawlett and Callum Brittain were absent in the EFL Trophy in midweek.
Robbie Muirhead and Paul Downing could be in line for recalls should Neilson want to make changes after the heavy loss at Ewood Park last time out.