By Sam AveryMichael Harriman's third goal of the season secured back-to-back wins for the Blues and a place at the top of League 2.
It was a particularly quiet start to the game with little action in front of goal - just a few shots off target for both sides in the early stages.
Then midway through the first half, Stephen McGinn wasn't far away with an effort from just outside the box that just missed the top corner. Towards the end of the second half, Cambridge goalkeeper Chris Dunn was called into action to deny a fierce right-footed volley by Harriman at his near post.
It was the perfect start to the second half for Wycombe, as Chris Dunn was sent off with a straight red card after rushing off his goal line to prevent Chairboys striker Gozie Ugwu from scoring, who was clean through on goal. It was the linesman who flagged for the foul inside the area and it was up to the referee Stuart Attwell to produce the red card for the keeper.
Sam Beasant, the substitute goalkeeper, immediately faced his first task; to try was to try and stop Garry Thompson's penalty, which he did, guessing correctly to dive down to his right to deny the soft spot-kick from the 34 year-old.
Wycombe needed to make the one-man advantage count and take the lead, which nearly happened through three big chances for the hosts within a matter of minutes. Firstly, Luke O'Nien tried his luck with a first-time shot from 35 yards which was inches away from finding the near top corner. Harriman's cross from the right bounced back off the crossbar but Marcus Bean's header on the rebound was straight at Beasant in goal. Bean had another glorious opportunity when his side-foot shot from close range hit the upright.
Cambridge United's resilient defence finally broke, no more than eight minutes later, when Michael Harriman hit a beauty, off the underside of the bar and in from outside the box with just 20 minutes left to play.
Gozie Ugwu could well have sealed the victory with a second goal in stoppage time when a long ball up field was brought down by him and he powered past defender Greg Taylor, but he couldn't quite find the finish after going through on goal and was denied by Beasant.
The win means that Wycombe have won 8 out of 9 home matches against Cambridge United in all competitions.