Oxford claimed victory over Bury thanks to a late Johnny Mullins goal.
Danny Rose put the U's ahead on the half-hour with a 25-yard free-kick.
Shakers midfielder Tom Soares smashed home Craig Jones's cross in the 70th minute before the hosts retook the lead when defender Mullins turned in David Hunt's set-piece 10 minutes later.
Bury's Nathan Cameron was then shown a second yellow card just moments after being cautioned for the foul that ultimately led to Oxford's winner.
VIEW FROM THE DRESSING ROOM
Bury manager Kevin Blackwell told BBC Radio Manchester:
"We just need a little bit of luck to change our way, but this side has been put together in five weeks and look at what they did to Oxford today.
"We did more than enough to win the game. We thoroughly dominated in the second half, they had one shot on target in the first half, and unfortunately we've lost the game.
"At the moment, it's just not dropping for us."
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