Sam Nombe's late goal earned Exeter a 1-0 victory at Oxford and a second successive away win after their 4-3 triumph at Bristol Rovers three days earlier.
They caught the U's on the break in the 79th minute and although Ed McGinty parried Jay Stansfield's shot, Nombe converted when the ball ran loose for his 13th goal of the campaign.
Josh Key almost made it two moments later but McGinty turned his curling effort against a post.
It was an impressive response from the Grecians following two heavy defeats by Oxford earlier in the season.
The U's dominated first-half possession and it needed a good save by Jamal Blackman to keep out Tyler Goodrham's header from Yanic Wildschut's fine cross.
Just before the break Matty Taylor was unlucky to see his shot come back off a post after a surging run from Marcus McGuane.
Blackman turned aside Cameron Brannagan's fierce drive.
At the other end Elliott Moore's superb block denied Key when he ran on to Stansfield's cross and rounded the goalkeeper.