It was back to league action for the young Blues on Friday afternoon as they played host to Shrewsbury Town at Creighton.
And it was a game packed wth incident as the 10-man home side left it to almost the final kick of the day to claim the point they'd worked so hard for.
The encounter started at a frantic pace and Lewis Bell looked an effective out-ball as he twice skipped past the right back before bearing down on goal.
Bell was through again early in the piece, but his effort on the run sailed over the bar, with the favour being returned at the other end when the Shrews mounted their first attack of the day.
Both sides were strong in the tackle, with no quarter given anywhere on the pitch, and United had half a shout for a penalty when Fishburn tumbled in the box. The big forward claimed his heel had been clipped but the referee showed no interest.
Right back Jack Ellis was precise with a rolled free kick which found Bell with his back to goal, and a toe poke on the spin had to be gathered by the keeper.
A booking from nothing for Elliott Day - given as he cleared the ball, which struck a Shrews man on the head, just as the whisltle was blown for a free kick - proved to be pivotal later in the half, despite the fact that nobody could believe the yellow card had been given.
Shrewsbury started to ask questions and Robinson was at his best on 22 minutes when he spread himself to make a fine save as an opposing forward broke through.
The visitors then missed what looked to be an easy chance when they cut down the right flank before floating a cross towards the unmarked number nine. He tried to glance the ball into the bottom corner but succeeded only in popping it the wrong side of the upright.
Carlisle responded with a good move which saw Bell rattle a cross into the box. It broke for Fishburn, at close range, but he was off balance and the stopper was able to close him down.
The hosts were made to pay for the miss when another move down the right wing brought a drilled pass into the six-yard area. All that was needed was a touch, and that was applied, albeit with a scuff that eventually took the effort over the line.
United were stung, and a Bell effort on the run wasn't too far away as he tried to make something happen. Leslie then dipped a 25-yard free kick straight at the keeper, and Walton couldn't quite squeeze it past the advancing glovesman as he went one-on-one when he latched onto another good through ball.
Time added on for the half brought disaster for Elliott Day as he flew into a tackle on the halfway line. The referee showed a yellow, and then a red as he sent the centre back off the pitch and back to the dug outs.
The 10-man Blues came out of the second half blocks determined to make a fist of it and they were awarded an immediate penalty when Fishburn had his legs taken. Lewis Bell placed the ball on the spot but the keeper guessed the right way to make a two-handed save.
Carlisle shook the disappointment off and a raking pass sent Watt clean through as the hosts continued to work hard. The wide man tried to lob the onrushing keeper but he was ready for it and he made a jumping one-handed save.
Shrewsbury almost killed the game off just past the hour when tenacity brought a shot which shaved the top of the bar, when it looked much easier to score.
United pressed forward, depsite the one-man disadvantage, and twice balls fizzed across the face of goal just begging to be put away.
Watt forced a save from a tight angle, with the home side going for it, and there was yet more controversy moments later when Bell and Watt combined after riding a tackle on the touchline.
DJ Taylor smashed the cross into the back of the net, and it was at that point that the linesman decided to raise his flag to say that the ball had gone out fpr a throw much earlier in the move.
Half chances came and went for United, but their hard work was finally rewarded deep into time added on when Taylor centred under pressure. The ball ricocheted and spun free, and Sam Fishburn was in close attendance as it finally found its way into the nets.
And the Blues almost won it with the last kick of the game when Fishburn showed good awareness to bring Danny Hill into play. He took a touch then drilled a rasping drive on the run, but it had too much on it and it whipped over the target.
United - Robinson, Ellis, Day, Barnett, Kilsby, Rooks (Taylor 59), Walton, Leslie, Watt (Hill 75), Fishburn, Bell. Subs - Breeze, Simons.
Goal - Fishburn (90+5)
Bookings - Day (19 & 45 - sent off)