Cambridge claimed a critical victory and local bragging rights by beating arch-rivals Peterborough 2-0.
The Posh missed a good chance on 38 minutes when Ephron Mason-Clark took down Frankie Kent’s long ball but fired off target as he ran into the box.
Instead it was the hosts who found the opening goal in the final seconds of the first half, through club great Harrison Dunk.
Conor McGrandles delivered a corner and Dunk, on his 452nd U’s appearance, peeled away to score unmarked from close range.
A critical phase of the match came on 66 minutes, when Dimi Mitov got down well to deny Nathanael Ogbeta to preserve Cambridge’s lead seconds before they went up the other end it made it 2-0.
Liam Bennett progressed down the right and pulled the ball back to Sam Smith, who smashed an effort in off the upright.
Mitov was called on to make a big save from Jack Taylor’s header soon afterwards to ensure Cambridge made it four games unbeaten in their bid to avoid the drop.