Oxford United have edged a step closer to the FA Cup fourth round by earning a 2-0 lead over Charlton Athletic at the halfway stage of their third-round clash.
The home supporters were shocked in the 13th minute when Johnny Mullins collected a pass from Scott Davies before striking a deflected effort past Ben Hamer.
Charlton fought back after falling behind but they struggled to pick the correct pass in the final third of the pitch as the stubborn Oxford defence frustrated the hosts.
It was the League Two side that scored the second goal of the game in the 24th minute, when James Constable picked out Davies and his shot proved to be too powerful for Hamer to keep out.
Sean Rigg was inches away from making it 3-0 just before the break when he fired an effort just over the crossbar.