The U's left it late to pick up an exhilarating victory against promotion-chasing Tranmere Rovers, with Junior Tchamadeu's first professional goal.
Junior Tchamadeu struck in the fourth minute of stoppage time to seal Wayne Brown's side all three points with a stunning volley from the edge of the penalty area.
The U's lined up with two changes to the side that fell to a 1-0 defeat against Forest Green Rovers on Monday evening, with Luke Hannant and Tom Dallison named in the team.
They took the places of Tom Eastman and Tyreik Wright, with the latter on international duty for the Irish U21 side.
Colchester United went closest to finding the net first, with Luke Hannant going agonisingly close to getting his first goal for the club. Seeing Joe Murphy rushing off is line, the U's winger chipped the visiting 'keeper, only to see the ball bounce just wide of the far post and out for a goal kick.
The U's felt hard-done by when the referee awarded them only a free kick on the edge of the penalty are after Cameron Coxe had got the better of his man before being downed, with Wayne Brown's side unable to make the best from the position.
At the other end, Shamal George had to make a couple of smart stops to prevent Nevitt and Hemmings from giving their side the lead, but Wayne Brown's side would have headed to the changing rooms at the break content with their performance in the first forty-five minutes.
Wayne Brown didn't wait long before making his first change in the second half, with John Akinde being withdrawn. Alan Judge was introduced into the action for the first time since the U's 2-2 draw at home to Leyton Orient.
The U's kept the pressure on the visitor's defence, but struggled to land a damaging blow on Tranmere's back four in the early stages of the second period. And they had to be careful to ensure they weren't hit on the break.
Shamal George was called into action, producing a fine save from Elliott Nevitt's swerving effort. Tranmere's top scorer fired a shot that looked destined for the top corner, but George came flying over to deny and keep the scores level.
Wayne Brown's final sub looked to be inspired at the full time whistle with Junior Tchamadeu brought on to volley home the winner from the edge of the penalty area. His first professional goal was a special one, with it sealing the three points and victory for the U's as he rifled home his shot.
And the three points mean the U's are now eleven points clear of the bottom two with seven to play. Colchester United move up to nineteenth in the table, with a trip to Harrogate on the horizon next weekend.
Colchester United starting XI: George, Chambers, Wiredu, Hannant (Tchamadeu 89'), Skuse, Sears, Chilvers, Dallison (Eastman 77'), Kenlock, Akinde (Judge 53'), Coxe.
Unused subs: Hornby, Andrews, Huws, Thomas.
Tranmere Rovers starting XI: Murphy, Dacres-Cogley, MacDonald, Davies, Merrie, Hemmings, Hawkes (Jollie 77'), Foley, Warrington, Nevitt, Clarke.
Unused subs: Knight-Percival, Spearing, McManaman, Maynard, McPake, Doohan.