Millwall Under 23s' run of four Professional Development League matches unbeaten came to an end on Tuesday afternoon as Charlton Athletic came out on top 2-1 at The Valley.
George Lapslie notched both goals for The Addicks either side of half-time, with Tom Elliott equalising for Kevin Nugent's side shortly into the second half.
The Lions remain fourth in the southern section of the League following the defeat, with Charlton climbing level on 36 points with a slightly inferior goal difference.
A number of first-team players featured for both sides, particularly Nugent's team, who were able to name Fred Onyedinma, Elliott and Jordan Archer among others. Numerous U18 players also started the match following their success to be offered their first professional deals just days ago.
The game started quietly in SE7, with The Lions seeing plenty of the ball and looking to force opportunities in wide areas.
It was however to be Charlton who took the lead midway through the half, as a pinpoint Mark Marshall cross from the right picked out Lapslie - the midfielder guiding a bullet header into the net at the far post.
Jason Euell's side grew in confidence following the opener, forcing a number of corners and breaks forward, and the hosts came inches away from doubling the lead when Tariqe Fosu steered a header onto the upright just before the half-time break.
Millwall began the second half undoubtedly the stronger side, looking to make amends by using the channels well and looking to find Elliott in the centre. And this approach paid off 10 minutes into the half as a good burst from Onyedinma down the left allowed him space to find the big striker - whose initial header was kept out fantastically by Nathan Harness, before Elliott poked home the rebound to draw level.
Despite the encouraging signs for The Lions, it was the home side who recovered and managed to steal in for a winner with 20 minutes remaining. Striker Josh Parker - who had just moments earlier blazed over a golden chance from Marshall's cutback - won his header 12 yards from goal, picking out the run of Lapslie, who had pulled away in behind to divert home his second.
Millwall's late efforts to salvage a point were dealt with adequately by The Addicks, with Jesse Debrah finding space at the back post but opting to try and pick out Onyedinma in a crowded penalty area, when an effort on goal could have been the better option in The Lions' final chance.
Next up for Nugent's prospects is an opportunity to get back to winning ways on Monday (8th April), away at Nottingham Forest.
Millwall: Archer; McLaughlin, Debrah, Trialist A, Tiensia; Skalak, Hanson (Trialist B 75'), Mitchell, Onyedinma; Alexander (Trialist C 75'), Elliott. Subs not used: Wright, Topalloj, Skeffington.