United went to the Cambs Glass Abbey Stadium for their first League Two away day of the campaign fresh from an excellent midweek performance against Fleetwood Town.
The Cumbrians made three changes from their midweek outing with Nicky Adams, Hallam Hope and Tom Miller coming in for Jamie Devitt, Mike Jones and Shaun Miller as they kicked things off with a 4-4-2 formation.
An early Cambridge attack had to be dealt with as Ibehre found the ball at his feet with his back to goal, but Ellis and Joyce closed him down quickly to smother the danger.
Striker Richie Bennett missed a golden opportunity to put his side in in the lead with just five minutes on the clock when he latched onto a ball over the top. He shrugged off his marker to go one-on-one with Forde but he put too much on his shot as he tried to curl it past the stopper and it bent well wide of the upright.
Bennett went close again when a good build up left him with half a sight of the target. He struck it well from outside the box but Forde went full stretch to parry it away. Hope was onto the rebound but the flag was up for offside.
The Cumbrians took a deserved early lead when Lambe and Joyce exchanged passes on the edge of the area. The winger was left with plenty of space and he didn't disappoint as he swept a beauty of an effort into the bottom corner.
United stayed on the front-foot but they were caught light at the back when Ikpeazu jinked inside his marker with the ball at his feet. He went for glory from distance but his grasscutter shaved the outside of the post.
The Abbeymen equalised with their first meaningful attack when a looped delivery from Carroll was spilled by Bonham. Elito fell to the floor as he came under pressure from Liddle and the nippy midfielder made no mistake as he dusted himself off to slam the penalty past the Carlisle keeper.
Things tightened up after the goal but Carlisle created another good opening when Tom Miller kept a half-cleared corner alive. Bennett jumped high to meet it but his header lacked power and it was easy for Forde to grasp.
A long kick from Bonham caused more problems for the Cambridge defence as Bennett found Hope with a flick. The centre forward dropped a shoulder and went for the shot but a deflection made it comfortable for Forde to deal with.
Good football from the hosts left Ikpeazu in space and he fed the ball back for Ibehre to strike as the blue defence struggled to recover. The former-Blue unleashed a first time shot which was never going to trouble the target.
The big striker was a threat again moments later when a low cross was picked up by Berry. His attempt at a thunderbolt spooned high into the sky and the follow-up header from Ibehre had to be cleared off the line by Liddle.
The Blues cleared their lines quickly and Bennett stroked a 40-yard pass out to Adams who had set off on a run down the left flank. He twisted and turned and was unfortunate to see his right-foot shot hit a shin and drop kindly for Forde.
United almost regained the lead just before half time when a long throw from Miller eventually fell to Parkes. His stinger struck Bennett in the midriff but Forde did well to scramble across and palm it behind for a corner.
It was a short-lived reprieve for the home side though as Tom Miller rose highest to meet the set piece delivery. Forde did enough to tip that onto the bar and Davies was on hand to block as Hope tried to finish it off. Tom Parkes stayed alive and he wheeled away in celebration as he crunched a firm volley into the waiting net.
Bennett tried his luck with a snapshot from distance as the second half opened at a slower pace, but he couldn't keep it down and it sailed over the bar.
Things took a while to get going and it was a stunning Danny Grainger free kick which sparked things off when he put his boot through a gentle roll from Adams. Forde watched it all the way but he struggled to deal with it as it bent and dipped onto his punch.
Berry sent one just over at the other end as clear-cut chances became few and far between, with Cambridge pushing men forward without any real impact as Carlisle held their shape.
But United had a real scare late in the day when Ibehre guided a Davies cross at the top corner. Bonham got the slightest of touches to it to direct it onto the bar and he recovered sharply to scoop it up as it bounced free on the floor.
Hope scuffed a cut-back from Cosgrove wide as the clock ticked down, and the hosts sent men forward as they tried to rescue the game with a series of deliveries into the area. But the blue shirts did their jobs and deservedly took the three points home at the end of a very satisfying day.
Cambridge United - Elito (14 pen)
Carlisle United - Lambe (8), Parkes (39)
Cambridge United - Elito (51)
Carlisle United - Liddle (56), Parkes (76)
Cambridge United - Forde, Carroll, Deegan, Taylor, Legge, Berry, Ikpeazu, Ibehre, O'Neil (Mingoia 66), Elito (Dunk 66), Davies (Azeez 85). Subs - Mito, Osadebe, Brown, Howkins.
Carlisle United - Bonham, T Miller, Ellis, Parkes, Grainger, Lambe, Joyce, Liddle, Adams (Jones 81), Bennett (Cosgrove 73), Hope (Devitt, 86). Subs - George, S Miller, Holt, Egan.
Referee - Tom Nield
Attendance - 4,102 (364 away fans)