United kicked their league season off at the Abbey Stadium - the very place they played their last away league fixture prior to the Covid-19 lockdown way back in February.
The game was designated as League Two's official test fixture for the return of fans - but the wheels were taken off that on Thursday when stricter Covid-19 restrictions were put in place by the government, meaning it would be yet another behind closed doors event.
New signing Ethan Walker, in from Preston on a season-long loan, was drafted onto the bench with two changes made to the starting line up. Patrick and Kayode came in for Furman and Riley.
It was a warm late summer afternoon in Cambridgeshire and it was Callum Guy who took the first kick of the season when he set things off from the whistle.
There was early defending to do for the away side as Hannant won a corner, but the defensive shirts converged to see the danger away.
United responded with a quick break which saw Alessandra pick possession up in the centre circle. He spread it to Patrick, but the forward had his effort blocked as he reached the edge of the box.
Good pressure from the Blues saw Toure take the ball from Digby before pushing the amber line back. He used Patrick as a bounce board, and Guy took over with a 23-yard shot. That came off Taylor, which took the sting away, and the hosts worked hard to calm things down.
Cambridge looked to impose themselves and a firm challenge from Hannant meant Hayden had to poke it clear from inside his own six-yard area. Hoolahan was in space but a poor long-range volley from him skewed well wide.
The home side took the lead with just nine minutes on the clock when the ball spun loose as McDonald and Hayden jumped to head it clear. It was quickly spread to Hannant and he drew Farman off his line before clipping it into the far corner.
More danger came when Hoolahan pounced on a loose clearance. He wasted no time at all in getting it into the area and Ironside was disappointed as it whisked past his outstretched leg.
The lead was doubled just past the quarter hour when Digby was first to another ball that was spinning free in the middle areas. Knoyle went on the overlap, and his first-time cross brought a crisp headed finish from the experienced Paul Mullin.
There was better from Carlisle when a long throw from Kayode was flicked into the mix. Toure took it on his thigh but his attempt at a volley on the spin fell kindly for Mitov to gather.
Good work from Anderton prevented Digby from breaking through when he was found by Ironside, and a corner from Alessandra at the other end was inviting for Hayden, but Mitov scrambled to get fingertips to it and that was enough to take it way from the onrushing centre back.
Another good Alessandra set piece, this time a free kick from the right flank, was glanced by Anderton before an instinctive volley from Hayden took it over the target.
Trickery from Toure almost opened a gap, and the Cumbrians recovered the loose ball as it was hooked clear, and Patrick pulled wide to win a corner. A series of crosses followed, and a drilled first-timer from Anderton had to be charged down as the visitors continued to push.
United camped forward, and Toure was involved again as he fed it to Mellish. His toe-ender ricocheted to Patrick and the slightest of deflections was enough to send his goal bound attempt the wrong side of the upright.
More Carlisle pressure eventually led to Toure finding space on the left. He stepped inside his marker and a dipping, rasping curler was less than an inch away from finding the top corner.
Patrick rattled another one over as he linked with Alessandra, but Uniited had to drop deep when Ironside ghosted into the visiting area. Mullin wanted it, but Guy got in the way and Farman came off his line to scoop it up as the cross came in.
Patrick and Digby went in the book as tempers flared in time added on for the half, but there was more fire needed from the Blues in the second period as they went into the tunnel with a two-goal deficit to deal with.
Good pack hunting from Kayode and Toure brought an early second half free kick which had away shirts forward in numbers. Cambridge dealt with it, but they couldn't break clear and Patrick ran deep to recover the ball and whip it in from wide. Toure waved his hands in frustration as he found himself just too far away to make it count.
A Kayode header from a dipper of a corner from Alessandra spooned high into the sky, as he found himself to be quickly closed down, and Toure glanced one off his forehead and behind for a goal kick when Tanner picked him out.
It was another good visiting spell and half chances continued to flow as the strikers lined up in an attempt to turn the territorial advantage into a goal.
Hayden was next to go close when Tanner lobbed a high ball at the penalty spot. The defender got a touch, which had Mitov worried, but the keeper was able to relax when it bounced away to safety.
There was work to do at the other end when Knoyle dropped a shoulder before sending his cross in. Mullin threw himself at it, but Hayden stayed big to shepherd it away.
Preston teenager Ethan Walker made his debut with 25 minutes left to play, as he replaced Alessandra, and Joe Riley came on at the same time as the Blues looked to apply yet more pressure.
The corner count continued to tick over for United when a Toure floater was guided behind. Walker got involved and he twice shielded it before rolling it towards the penalty spot. Patrick had a shot blocked just as it appeared that it had opened right up for him.
All of the action was in the Cambridge half, with Kayode and Guy also closed down as they tried to get efforts at the nets, but there was a blow with 15 minutes left to play when Hayden dropped to the floor. He left the pitch to be replaced by Jack Armer.
The theme of the game from the moment the second goal had been conceded was Blue attacking, Amber defending, but the gate to the Abbey remained shut as the hosts protected their lead.
And there was a real sting in the tail when Cambridge chewed up the possession stats as Ironside found the bottom corner with a neat finish from 20-yards when he'd been picked out by Kyle Knoyle.
Seven minutes of time added on brought more Cumbrian deliveries, most notably from Guy, Anderton and Walker, and a fizzed near post grasscutter from Armer had to be swiped away by Knoyle.
But it was another blank scoresheet for the Blues as they headed north to regroup for next weekend's home game against Southend.
Cambridge United - Hannant (9), Mullin (16), Ironside (85)
Cambridge United - Digby (45)
Carlisle United - Patrick (45), Guy (77), Toure (88), Mellish (89)
Cambridge United - Mitov, Knoyle, Digby, Taylor (c), Hannant, O'Neil (May 28), Mullin (Knibbs 77), Dunk, Hoolahan (Iredale 69), Cundy, Ironside. Subs - Burton (gk), Dallas, Davies, Knowles.
Carlisle United - Farman, Tanner (Riley 65), Hayden (Armer 77), McDonald, Anderton (c), Guy, Mellish, Alessandra (Walker 65), Patrick, Kayode, Toure. Subs - Dewhurst (gk), Devine, Hunt, Reilly.
Referee - Paul Howard
Assistant Referee 1 - Garry Maskell
Assistant Referee 2 - Paul Lister
Fourth Official - Stephen Finch
Attendance - behind closed doors