Not only that, they are now within four points of fifteenth place, as the League One table has been blown wide open by the Easter fixtures.
Goals from Gavin Massey, Jacob Murphy and George Moncur sealed a memorable victory that means that the U's are now just two points from safety.
Colchester United gave their survival hopes a huge boost on Easter Monday, recording a 3-1 win with a scintillating second half display.
Tony Humes made only one change to his starting eleven that took three points from Vale Park with Sammie Szmodics replacing Alex Gilbey. Chris Porter took the captain’s armband.
The stop-start nature didn’t allow Colchester to build any kind of rhythm throughout the half and typically it then came to punish them as Barnsley took full advantage of a set piece play.
A soft free kick conceded out wide was floated in by Conor Hourihane and seemed to cause havoc in the box, George Waring was the man who got the ball over the line.
The second half looked to be following suit with the first as referee Hill brandished another yellow card, this time for Lewin Nyatanga of Barnsley.
Massey finally managed to get some space and provide some excitement racing down the left to win a corner for U’s which the South Stand faithful appreciated.
This marked a strong spell for U’s, in which Porter and Alex Wynter both had close range efforts kept out impressively by Tykes keeper Adam Davies.
With half an hour to play Humes made his first move to try and change the game, with Gilbey taking his place back from Szmodics.
However it was inform loanee Jacob Murphy that again made the difference, cutting in from the right he curled a ball across the box to the far post and there was Massey to slide it home, levelling the score.
Tom Eastman was called into action at the back with a goal-saving sliding block and minutes later he was at the other end, but unmarked could only send his header over the bar following a corner set piece.
The U’s continued to up the pressure and with just ten minutes to go they found their winner, this time Massey and Murphy swapped the roles of goal-creator and scorer.
Massey again had the better of his fullback and raced into the box before cutting the ball high to the back post where Murphy was positioned perfectly to head the ball home.
Before Barnsley had time to settle Massey was again embarrassing his full back, this time he cut the ball back to George Moncur who slotted the ball in from the edge of the box to kill the game.