A second-half fightback was not enough for Millwall's Under 23s on Tuesday afternoon as they suffered a first defeat in nine Professional Development League games, losing 3-2 to Colchester United.
Louis Dunne, Eoin McKeown and Tarique Hyde sent The U's into a 3-0 half-time lead, with Rob Harvey's stunning finish and Isaac Olaofe's late goal proving no more than consolation on an exciting afternoon in South London.
Kevin Nugent included first team players Jordan Archer, Conor McLaughlin, Byron Webster and Ryan Tunnicliffe in his starting XI, alongside the usual suspects of Danny McNamara, Jethro Hanson and Mason Saunders-Henry.
The U's took a two-goal lead inside nine minutes as first, five minutes in, Colchester opened the scoring through Dunne's superb free-kick, which curled into the top corner beyond the reach of Archer, before it was two shortly after as McKeown shrugged off the attentions of Webster and blasted home.
The attacking play was all Colchester's in the early stages and Ken Charles nearly made it three with 17 minutes on the clock, but he fired wide. Lewis White then tumbled in the penalty area at the other end, but referee Mr Skipper was unmoved.
Millwall's first attempt of the afternoon came from Webster, but he shot over from 30 yards out. White's cross evaded everyone and then a swift passing move between Olaofe and Tunnicliffe attempted to get things moving, but to no avail.
The Lions were starting to come into the game, but their task became more difficult three minutes from the half-time break as Hyde stroked home The U's third unmarked.
Any possible Millwall fightback began in the 56th minute as Harvey reduced the arrears with a smart finish from 30 yards out after goalkeeper Dillon Barnes fluffed his clearance.
Colchester were queuing up to regain their three-goal advantage on the hour-mark, but the ball ended up in the lower tier of the away end after goalscorer Dunne lofted a shot over the crossbar.
Just over 20 minutes from time Millwall almost grabbed a second, but Dillon Barnes' expertly saved Olaofe's goal-bound header from Saunders-Henry's cross.
With eight minutes to go the second arrived as Olaofe turned home McNamara's cross, and it looked as though the equaliser would arrive three minutes later, but after substitute George Alexander won the ball back and danced past the Colchester defence, his shot went agonisingly wide of the post.
Saunders-Henry then struck wide in injury-time as the unbeaten run came to an end.
Next up for the Under 23s is a London derby with Crystal Palace next Monday.
Millwall: Archer, McLaughlin, McNamara, Hanson, Webster, Stojsavljevic, Harvey, Tunnicliffe, Olaofe, White (Alexander 46'), Saunders-Henry. Subs: Topalloj, Sandford, Mitchell, Parker.
Scorer: Harvey 56', Olaofe 82'
Colchester United: D. Barnes, Brown, A. Barnes, Ward, Agboola, Fogno, Gondoh, Dunne, McKeown, Hyde, Charles. Subs: Hallett, Wind, Cook, Patino, Thomas.
Scorer: Dunne 5', McKeown 9', Hyde 42'
Booking: D. Barnes, A. Barnes
Referee: Mr. D. Skipper