Colchester extended their unbeaten run in Sky Bet League Two to nine games with a 1-0 win away at MK Dons.
Jack Payne sealed the points for Colchester with a late penalty against his former club before Callum Hendry was sent off in stoppage time for the hosts.
Defeat means the Dons are now winless in six, while Colchester picked up a first win in four after three straight draws.
Colchester had the better of a slow first half, with Lyle Taylor twice seeing efforts narrowly miss the mark.
Alex Gilbey then saw a shot skim just past a post in the final stages of the opening period.
The visitors came close early in the second half when John-Kymani Gordon hit a post before MK Dons nearly made the breakthrough when Scott Hogan saw his fine strike bounce off the frame of the goal.
The decisive moment came late on when the referee gave a penalty for a foul by Kane Thompson-Sommers on Payne. The midfielder duly scored the 87th-minute penalty.
Hendry was dismissed for a high boot on Kane Vincent-Young to add to the Dons’ misery.
