Jordan Rhodes scored twice and Dean Bowditch once as Town's reserves camefrom two goals behind to claim a 3-3 draw at Colchester's Weston Homes Community Stadium.
David Wright was back at right-back after his ankle ligament injury, while David Norris and Iván Campo, who started at centre-half, were in the side as they work towards full match fitness.
Both sides missed decent early chances, Fabian Batchelor forcing a good save from Shane Supple, while at the other end Mark Cousins blocked from Dean Bowditch at close range.
Jordan Rhodes should have done better when in space inside the area, but chipped the ball into Cousins's arms.
Colchester went in front in the 16th minute when Mitchell Nelson headed home from a corner. Four minutes later, Sunday Wasiu added to the U's lead when he twisted and turned inside the area, lost the ball but regained possession, then struck a low shot past Shane Supple.
Just after the half hour, Chris Kiwomya's men pulled a goal back. Tommy Smith's powerful header from a corner was saved, but Jordan Rhodes reacted quickest to slam home the rebound.
David Wright should have put the Blues back on terms in the 53rd minute but headed wide when unmarked at a corner.
Two minutes later, Dean Bowditch, playing in a deep-lying Pablo Couñago-esque role behind Rhodes and Haynes early in the second half, played a low ball across the six-yard box but no Town player was there to add the final touch.
On 59 the U's went further in front. Fabian Batchelor was allowed to bring the ball forward to the edge of the area unchallenged and hit a shot beyond Supple. It was a poor goal to concede but was largely against the run of play.
Rhodes shot straight at Cousins, then came close with a header from a corner which flew narrowly wide. Balkestein, who moved to centre-half after Campo had been replaced, headed a corner over when he ought to have scored.
Town pulled a goal back after a fine move in the 66th minute, Kurt Robinson cutting in from the left and laying the ball back to Dean Bowditch, who beat the keeper from 10 yards.
The Blues had by now taken complete control and were laying siege to the Colchester penalty area. Sub Murphy almost embarrassed Cousins with a shot at his near post, then Rhodes had a shot blocked inside the area.
With two minutes left on the clock, Rhodes levelled the scores. Cousins had brilliantly saved the striker's effort from close range from Murphy's cross, but from the resultant corner, the 18-year-old nodded Tommy Smith's header into the net from close range.
Given the strength of the side on show, Town were disappointing before the break, never really showing their extra class. They improved after the break with Norris impressive in the centre of midfield.
David Wright looked unhampered by his recent ankle ligament injury, while Campo strolled through the game, making the odd raking pass. Neither Jaime Peters nor Danny Haynes managed to send in much of quality from the flanks, while Paul Murphy and Kurt Robinson put in impressive late cameos.
Boss Jim Magilton watched the second half, while coaches Bryan Klug, Steve Foley and Charlie Woods were present for the full 90. Also in the crowd were Southend boss Steve Tilson and Charlton assistant manager Phil Parkinson.
Reserves: Supple, Wright, Balkestein, Reason, Smith, Campo (Robinson 66), Peters, Norris, Rhodes, Bowditch, Haynes (Murphy 66). Unused: Ward, Watson, Daniels.