Goals from Sammie Szmodics and Kane Vincent-Young secured a 2-1 victory for Colchester United over Millwall on Tuesday night.
Substitute Jed Wallace netted a consolation for The Lions in the 90th minute with a delightful finish.
As promised, manager Neil Harris opted to shake up his starting XI, meaning a first appearance in goal for Ben Amos. Byron Webster, Fred Onyedinma and George Saville also began the game.
Vincent-Young and Szmodics tested the Millwall defence with driving runs early into the contest, whilst at the other end Shane Ferguson's free-kick was tipped over the crossbar by Dillon Barnes.
Colchester took the lead in the 20th minute as a through-ball sent Szmodics away to slot home past Amos. Three minutes later The Lions looked to level, but Aiden O'Brien's curler was superbly palmed wide by Barnes. From the corner-kick, Fred Onyedinma headed over.
With 31 minutes on the clock the lead was doubled. A neat interchange of passes saw Vincent-Young collect the ball just outside the six-yard box before smashing the ball into the roof of the net, giving Amos no chance.
The first-half ended and the second-half begun with next to no action at either end, prompting Harris to make a double substitution, bringing on Mahlon Romeo and Lee Gregory for Ferguson and James Meredith.
Millwall began to gain a foothold and pressure Colchester's back four as the last 20 minutes approached, but they were unable to pierce the resolute defence as The U's looked to keep a clean sheet.
Wallace and Jake Cooper were the latest subs to make an appearance before Steve Morison struck over from Onyedinma's knockdown 10 minutes from time.
Colchester substitute Luke Norris smacked a shot against the crossbar near the end of the 90 minutes, before Wallace curled a delightful strike home at the conclusion to reduce the arrears.
Colchester United: Barnes, Jackson, Lapslie, Prosser, Kent, Senior, Pell, Szmodics, Dickenson, Vincent-Young, Nouble. Subs: Gilmartin, Norris, Comley, Wright, Kensdale, Eastman, Mandron, Collins, Clampin.
Scorer: Szmodics 20', Vincent-Young 31'
Millwall: Amos, McLaughlin, Meredith (Gregory 62'), Onyedinma, Ferguson (Romeo 62'), Webster (Cooper 75'), Tunnicliffe, Morison, O'Brien (J. Wallace 75'), Saville, M. Wallace. Subs: Martin, Hutchinson, Williams, Thompson, Elliott, Brown.
Scorer: Wallace 90'
Referee: Mr. C Hicks