Substitute John-Kymani Gordon netted the only goal as Colchester registered their first away win of the season with a 1-0 triumph over Grimsby.
Harry Anderson had two opportunities inside the first seven minutes for the visitors, firing over from a low-whipped cross by Samson Tovide before heading straight at goalkeeper Jordan Wright from point-blank range.
The hosts hit back with a big chance of their own in the 15th minute but Callum Ainley was unable to beat keeper Matt Macey as he was found with space to shoot in the box by Denver Hume.
The U’s had a goal chalked off in the 65th minute as Anderson was deemed offside after turning in a knockdown from a corner.
Tovide then forced a smart save from Wright at his near post with a quick turn and shot in the box.
But Gordon struck the winner in the 78th minute, just three minutes after coming on, as he tucked the ball past Wright into the bottom-right corner.
