Exeter recorded their fourth win in a row in a six-goal thriller at Oxford.
Jamie Cureton scored twice with Scot Bennett and John O'Flynn also on-target.
The Grecians were 2-0 up at the break. Cureton opened the scoring after just 11 minutes with a shot from 20 yards, then Bennett's header doubled the advantage.
Cureton made it 3-0 early in the second half with an individual effort, before Oxford staged a two goal comeback.
O'Flynn made the game safe in the 72nd minute, and the hosts ended the match with ten men after James Constable was sent-off for two bookable offences.