Colchester edged out Barrow 3-2 on Friday night, in a game where both sides finished with 10 men.
Jordan Stevens put the hosts in front after 25 minutes of his second appearance for the club, before Alan Judge and Freddie Sears scored within three minutes of one another to turn the game in Colchester's favour before the break.
Luke Chambers was dismissed for the visitors after he picked up a second booking with 22 minutes to play, with Ollie Banks then levelling the game from the penalty spot shortly afterwards.
As the drama continued in Cumbria, Tom Eastman restored United's lead with what proved to be the winner 10 minutes from time, while in the final minute of the 90, Jamie Jones also saw red for a second yellow card.
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