Pat Baldwin completed 90 minutes for Colchester's reserves on Monday night on his long-awaited return from a fractured toe.
The defender sustained the injury in the 2-2 draw with Yeovil at the start of October but finally got back to action in a 3-1 friendly defeat against West Ham.
Steven Gillespie put the U's in front after just 18 minutes, seeing off the attention of three players before firing a low shot across goal and into the bottom corner.
United stopper Mark Cousins pulled out a couple of great saves but was helpless to prevent George Moncur drawing level from the penalty spot on the half-hour mark, before second-half goals from Brian Montenegro and Eoin Wearen clinched matters for the Hammers.
The clash also saw the likes of John-Joe O'Toole, Ben Coker and Tom Eastman get vital match practice for the U's.