Cheltenham’s battling second half efforts weren’t enough to prevent Colchester leaving the Jonny-Rocks Stadium with all three points.
A first-half double from Luke Norris sent the visitors in leading at half-time, but Kevin Dawson’s early second half strike did give the Robins hope of a comeback.
However, a late penalty from Harry Pell gave the visitors victory despite the best efforts of caretaker manager Russell Milton’s side in the second forty-five.
After a scrappy start, the game burst into life when Cheltenham midfielder Nigel Atangana conceded a penalty after denying Colchester’s Luke Norris a strike on goal just inside the box.
The forward picked himself up and made no mistake in converting from the spot past Scott Flinders to give the visitors the advantage.
Norris came close to doubling his tally shortly after when he met a deep cross at the back-post, but his header could only find the side-netting.
He made up for that miss with a well taken free-kick after a foul 25-yards out presented Colchester with a shooting opportunity which they took as Norris scored his second with a strike that left Flinders helpless.
Sam Jones came close for the Robins after dodging a couple of challenges outside the area before firing a shot just wide of goalkeeper Dillon Barnes’ post, but it was Ryan Broom who came closest for the hosts.
Space opened up for Broom just outside the box, and it took a solid save from the Colchester stopper to tip his effort over the bar, in the final act of the half.
Town started the second half well and forced an early set piece just outside the area after Manny Duku was taken out during a counter-attack, but Broom’s free-kick failed to beat the wall.
However, Cheltenham’s good start to the half was rewarded soon after following good hold-up play from Jones in the box.
The striker controlled a drilled ball and laid it off to the onrushing Kevin Dawson who fired home a much-needed response for the Robins.
Cheltenham continued in the same vein with the influential Broom at the heart of everything being created and his direct running was a constant threat to Colchester’s defence and it nearly created an opening, but his effort curled just wide.
Jones was another who was heavily involved in the second period and had several chances; glancing a header just wide of the post before dragging an effort wayward from a good shooting position.
But it was substitute Tyrone Barnett who had a big opportunity to mark his Robins debut with an important goal.
Jacob Maddox left a low ball into the box for Barnett and despite the goal opening up, he fired a volley just wide of the post.
Despite all of Town’s efforts, they were undone by another penalty after Sammie Szmodics was brought to the ground by Broom during a counter-attack.
It was former Cheltenham player Harry Pell who sealed the points for the away side after his spot-kick found the top corner in a disappointing afternoon for the Robins.
CHELTENHAM TOWN (4-4-2): Flinders, Mullins, Atangana, Dawson, Duku (Mooney 54), Broom, Boyle (Kalala 89), Maddox, Forster (Barnett 78), Jones, Field. Subs: Tozer, Lloyd, Lovett (Gk), Clements.
COLCHESTER UNITED (4-3-3): Barnes, Jackson, Prosser, Kent, Pell, Norris (Norris 65), Szmodics, Comley, Eastman, Vincent-Young, Nouble. Subs: Senior, Mandron, Barnes, Wright, Rooney, Ross, Collins.
REFEREE: O Yates
ATTENDANCE: 2,789 (198 from Colchester)