Sutton moved up to sixth in League Two with a deserved 3-1 win at 10-man Colchester.
Colchester took a second-minute lead through Freddie Sears, who controlled Charlie Daniels’ cross in the area before firing home a low shot.
But Sutton levelled after 12 minutes when David Ajiboye beat Daniels to score at the far post following skipper Rob Milsom’s deep cross.
Things took a real turn for the worse for Colchester when they fell behind and went down to 10 men.
Isaac Olaofe prodded the ball towards goal after goalkeeper Shamal George had dropped a corner and Samson Tovide was adjudged to have deliberately handled on the goal-line and sent off by referee Bobby Madley, with Milsom converting the resultant penalty.
Omar Bugiel almost added to Sutton’s lead in first-half stoppage-time with a low shot that sailed just wide.
But the visitors wrapped up victory in the 61st minute through Ben Goodliffe, whose glancing header from Milsom’s free-kick into the area flew in.