Second half penalties sink the Blues ...Two soft second half penalties helped to seal United's fate on an afternoon when they just couldn't get themselves going and they were ultimately made to pay the price.
Carlisle had two early long throws with Norris well placed to grasp the flick on from Ibehre from the second attempt from just beneath his bar.
A long range shot from Berry sailed over the target as Cambridge tried to push United back but the game took a while to get going as Leon Legge battled against an early nose injury.
The Cumbrians had the visitors worried when Ibehre released Adams on the left. His low delivery was eventually put behind by Wharton as Ibehre lurked.
Cambridge fashioned a clear sight of goal on the quarter hour when Miller nodded a delivery from Halliday to edge of the area. Maris controlled it and he was a whisker away as he aimed for the far post.
Another low cross from Adams found Ibehre with his back to goal as the action switched to the other end and the big striker took everyone by surprise when he volleyed on the spin. It screwed off his boot and dropped over the bar.
United enjoyed a lot of possession and deliveries from Grainger, Adams and O'Sullivan signalled that they were trying to make things happen. There was half a shout for a penalty turned away when Lambe dropped to the floor as he shaped to wrap his boot round a pass from O'Sullivan. The officials showed no interest in the incident at all.
Clear cut chances were few and far between through a tight first half and Ibehre was frustrated when he sent a header from an Adams cross high into the sky.
Carlisle ended the half on the front foot with more determined work from O'Sullivan on the edge of the box. Ibehre and Lambe had half volleys blocked but Cambridge stayed compact and hooked the loose ball away.
The visitors attacked first at the start of the second half but the flurry of activity came to an end when Clark crunched a wild shot into the Waterworks End.
A cut back from O'Sullivan was stopped at the near post when Adams sent him on the overlap, and a deep cross from Adams picked out Lambe as the hosts continued to try to increase the tempo. The wide man got there but his header fell just the wrong side of the upright.
The men from the Abbey attacked at pace when Jones was robbed of possession on the half way line. It needed an excellent tackle from Grainger inside his own area to stifle the danger.
United were rocked back on their heels just after the hour when Berry toppled to the floor under pressure from Liddle. The referee pointed to the spot and substitute Medy Elito smashed the kick into the roof of the net.
Mike Jones had to leave the field as he failed to recover from an ankle injury and the afternoon got even worse when Adams battled with Clark for another loose ball. The tangle led to another spot kick and Elito kept his cool to score his second of the afternoon.
Keeper Mark Gillespie prevented Elito from bagging a hat-trick with an excellent save late in the day, but the big striker snatched it anyway when he rattled a stinger into the net - after James Bailey had been sent off for violent conduct - to rub salt into the Carlisle wounds.
Cambridge United - Elito (66 pen & 71 pen, 90)
Carlisle United - Brisley (69), Waring (87)
Bailey sent off (90 - straight red card)
Cambridge United - Mingoia (76), Maris (83)
Carlisle United - Gillespie, T Miller (S Miller 62), Liddle, Brisley, Grainger, O'Sullivan, Bailey, Jones, Adams, Lambe (Proctor 76), Ibehre (Waring 62). Subs - Crocombe, Joyce, Salkeld, McQueen.
Cambridge United - Norris, Taylor, Dunne, Legge, Mingoia, Berry, Wharton, McDonagh (Elito 46), Maris (Dunk 90), Clark (Lewis 76), Halliday. Subs - Gregory, Roberts, Williamson, Carroll.
Referee - Mr Robert Jones
Attendance - 4,427 (207 away fans)