Goals from Joe Taylor and Chay Cooper secured the win for the U's, a hard-fought victory against the Ammies.
Colchester United were looking to bounce back from a tough defeat at Wrexham at home to Salford on Friday night.
The U’s had the opportunity to draw level with their opponents if they secured all three points and at the same time would end a run of five League Two losses in a row.
The first half was an evenly contested affair with both sides having huge opportunities to take the lead.
For Salford a golden chance fell to Conor McAleny – who failed to beat Owen Goodman after being played through into the penalty box.
At the other end, Ellis Iandolo looked to set to turn the ball into an empty net but for a late Salford touch that deflected the ball over.
Eventually the U’s broke the deadlock through Joe Taylor, who turned home from close range for his eleventh goal of the season.
The second half did not see as much action, but there were still opportunities for the U’s.
Jayden Fevrier sent two great strikes towards goal after cutting in from the right, forcing a couple of great saves.
At the other end, substitute Matt Smith was proving to be a handful with his significant aerial threat.
As the game drew to a close, things were becoming scrappy as tired legs from both sides looked to see it through until the end.
And it would be the U’s who prevailed with a second goal late on courtesy of Chay Cooper!
A loose touch from Ethan Ingram was picked up by John Akinde who played the speedster forward and he had no problem slamming the ball into the net.
Salford did provide an instant response through McAleny, who struck the ball sweetly into the top corner from range.
But it would not be enough for the visitors and Colchester picked up three huge points at the JobServe Community Stadium.
Matty Etherington made two changes to the side that lost at Wrexham last weekend, with Iandolo replacing Will Greenidge and captain Connor Hall returning to the side after recovering from injury.
The U’s started brightly, fashioning an early chance for Cameron McGeehan, who found space in the box to drill a shot at Alex Cairns in goal before sending his follow up just past the post.
Salford had an early opportunity themselves after McAleny turned in the final third but a sliding challenge from Zach Mitchell prevented the striker from getting his shot off.
A few minutes later Ryan Watson registered the visitors first shot on target, hitting a first time shot into the stomach of Owen Goodman in goal.
Arthur Read was the first man into the book for preventing Salford from breaking in behind and tugging his man back.
At the other end, a good spell of possession ended with Read firing a dangerous ball across the box but there were no blue and white shirts there to tap home.
The number sixteen was at it again a few minutes later, twisting and turning in the box after breaking in behind but his powerful drive would only sting the palms of Cairns.
With thirty minutes on the clock, the U’s worked a short corner well and Matt Jay found space in the box. Another effort on goal was registered but again Salford had enough numbers behind the ball to prevent any danger.
Hall was next to be cautioned for blocking his runner on the near side, but the U’s were able to deal with the dangerous free-kick that followed.
A third booking for the home side followed shortly after. This time Joe Taylor was cautioned for jumping into the goalkeeper.
The Ammies came closest to taking the lead on the thirty-five-minute mark. McAleny played a neat one-two and only had the goalkeeper to beat but Goodman made himself big enough to prevent the opener.
Ingram was the first man to be shown a yellow card for Salford after the defender prevented Chilvers pouncing on a loose touch in his own half.
Iandolo had a magnificent chance to find the breakthrough. The full-back found himself free at the back post and had an empty net in front of him but a Salford player managed to throw himself towards the ball to deflect it over.
But only a few minutes later the U’s had the lead.
Taylor’s persistence paid off as he placed home on the turn after a clever dummy from Mitchell left him free by the six-yard box.
Salford had a late free-kick and pumped the ball into the box but it was dealt with calmly by Mandela Egbo before the referee blew for half time.
The match resumed with no changes from either side and Etherington’s men started on the front foot as they looked to consolidate their lead.
But a few times Salford found some space on the counter-attack and Mitchell was alert to put a stop to McAleny’s darting run in behind.
Fevrier showed his pace and went on a darting run from his own half, beating several players before playing a ball in behind for Matt Jay, who was deemed to be offside, much to the displeasure of the crowd.
The first changes of the night were made by the U’s, with Hall and Iandolo, both still working up to full fitness, making way for Tom Dallison and Al-Amin Kazeem.
And there was almost an instant impact with fresh legs on the pitch. Cameron McGeehan shot from close range and the goalkeeper got down well to push it away for a corner.
Fevrier was at it again moment later, this time curling a left-footed effort towards the far corner and forcing another great save from Cairns.
A lapse in concentration in the middle of the park saw substitute Matty Lund set free on the left-hand side and he struck the ball first time and sent a curling effort dipping onto the roof of the net.
More changes were made by Etherington for the final twenty minute. Taylor and Jay both made way for John Akinde and Chay Cooper.
Mitchell opted for a late lunge and was the next victim in the referee’s book and the resulting Salford free-kick was met by Smith and eventually put behind by Egbo.
Ingram was lucky to escape a second yellow card for a late tackle on Kazeem, who opted to give the defender a stern talking to instead.
Smith was finding a lot of joy in the box as the clock ran down. Salford were finding the target man with their crosses and he sent a powerful header just over the bar with four minutes left to play.
With the Ammies committing men forward in the dying seconds, Colchester capitalised and scored their second.
Akinde put Cooper through who raced in and powered past Cairns in goal to send the crowd into raptures.
But Salford responded instantly with a special strike from McAleny who rifled in off the crossbar from outside of the box.
Goodman was forced into a fine save by Smith with less than two minutes to play and that would prove to be the final big chance of the match as the U’s walked away with a huge win.
Colchester XI: Goodman, Iandolo (Kazeem, 58), Hall (Dallison, 58), Jay (Cooper, 71), Chilvers, McGeehan, Mitchell, Read, Egbo, Taylor (Akinde, 71), Fevrier (Greenidge, 90+3)
Subs: Hornby, Greenidge, Dallison, Hopper, Akinde, Kazeem, Cooper
Salford XI: Cairns, Ingram, John, Mariappa, Watt, Watson, McLennan, Tilt, McAleny, N’Mai (Smith, 61), Humbles (Lund, 61)
Subs: Wright, Lund, Smith, Berkoe, Da Costa, Hamman, Luamba
Attendance: 3,560 (114 away)