Carlisle boss Paul Simpson rued that there was “nobody else to blame but ourselves” following his side’s 1-0 defeat at the Abbey Stadium.
The Cumbrians produced a disappointing performance to lose to a Cambridge side that were on an eight-game winless run in League One.
Sub George Thomas headed the winning goal for the Us, before Simpson’s side ended the match with nine men following the late dismissals of Jack Armer and Alfie McCalmont.
“Let’s not look at blaming anybody else, it’s our own fault,” he continued. “If you don’t do the basics well then you don’t get anything out of the game, and unfortunately we didn’t.
“The biggest disappointment is, after a really good week of two really good performances against Portsmouth and on Tuesday night, today we’ve been way off it. We’ve turned over possession so many times, we haven’t won our duels enough.
“Jack Armer’s sending-off, it’s a lazy challenge to get that second yellow card. Alfie, I feel for him a little bit. I have to say it probably is a red card because of the way his foot has come up, but he has no idea the lad is there. He didn’t do it intentionally.
“I accept that we can’t play brilliantly every game but you have to get a consistent level of doing the basics right, and that’s where we’ve let ourselves down. I do think we have let ourselves down today because I felt this was a missed opportunity.”
Mark Bonner felt Cambridge deserved the three points as they recorded their first victory since September 4.
It came after Tuesday’s draw with leaders Portsmouth, following defeat at previously winless Cheltenham last weekend.
“We needed a week like we’ve had this week, we needed a result like that today,” said Bonner.
“Their best chance was probably in the first minute. We got countered too easily and too often in the first half – they caught us out a few times.
“The wide play was miles better in the second half, and we threatened the back of them much better.
“In the second half I thought we had complete control of the game, were really dominant in their half and deserved the goal when it came.
“The end of the game was a bit weird, really, because it felt like it went on forever and we sort of forgot we were playing against nine players. There was more space than there needed to be.
“We looked edgy towards the end but in the end I thought it was really controlled and fairly dominant. Other than the first minute we weren’t under huge threat.
“We’ve built two good performances this week and four good points.”
