Second half goals from Tom Eastman and Jevani Brown turn the game on its head as the U's run out 2-1 winners.
Colchester United have beaten ten-man Wealdstone who lead at the break through a Moses Emmanuel strike, despite Danny Green being dismissed for a late challenge.
A better performance from the U's in the second half saw them put two goals past Sam Beasent in goal to ensure the trip back to Essex was a happy one.
Tom Eastman steered the ball in at the back post from a Tommy Smith header, while Jevani Brown slid in to score the U's winning goal after a fine driven cross from Cohen Bramall.
STARTING XI: Gerken, Scarlett, Eastman, Smith, Bramall, Pell, Stevenson, Chilvers, Harriott, Poku, Brown.
The opening half hour of the game was even, with a couple of half chances for the U's while the hosts had a penalty appeal denied.
There was just five minutes on the clock when Wealdstone thought they should have had a penalty. Dennnon Lewis sprinted into the area before dinking a cross into the middle. Connor Smith's header was blocked by Harry Pell with the home side shouting for a spot kick. The referee disagreed and play continued.
Jevani Brown was the target man for the U's attacking line, and was unlucky not to set up the opening goal of the game when he got the better of Sam Beasant in goal, but couldn't pick out Chilvers who was making a late run into the area.
Brown went close again with twenty-five minutes played when he saw his effort deflected away from the goal before Noah Chilvers was closed down before he could tap into the empty net.
With five minutes left to play of the first half, Wealdstone were reduced to ten men when Danny Green was shown straight red card. He late challenge on Ben Stevenson was enough to be given his marching orders.
As the game headed for half time, the hosts took the lead. Dennon Lewis' low cross was lifted against the bar by Ross Lafayette, before Moses Emmanuel was able to poke the ball beyond Gerken and give his side the lead at the break.
It took the U's just seven minutes to find an equaliser in the second half. Tom Eastman was lurking at the back post and tapped in Tommy Smith's initial effort to level the scores.
With sixty minutes played the U's made four changes with Miquel Scarlett, Tom Eastman, Noah Chilvers and Ben Stevenson being replaced by Miles Welch-Hayes, Marley Marshall-Miranda, Omar Sowunmi and Courtney Senior.
Just one minute later and Colchester United took the lead. A first time low cross from Cohen Bramall was slid into the back of the net by Jevani Brown to give the U's a 2-1 lead.
The U's made more changes when scorer of the second goal, Jevani Brown and Callum Harriott were replaced by Jake Hutchinson and Michael Fernandes with just over twenty minutes to play.
Hutchinson was unlucky not to add a third for the U's when Miles Welch-Hayes drilled a cross into the penalty area. THe ball was just too far ahead of the U's frontman who was stretching but unable to reach.
Dean Gerken had to still be on his guard though as Wealdstone pressed for an equaliser, saving two good efforts from Danny Parish.
Parish first had a deflected shot that Gerken had to pounce on with fifteen to play. The U's 'keeper then had to scramble across his goal to deny Parish once again with four minutes remaining.
The U's were able to soak up all the late pressure that was thrown at them, as they come out on top against National League Wealdstone.