Kevin Nugent's young Lions stretched their unbeaten run to six matches on Monday afternoon as Lewis White's free kick was enough to beat Charlton Athletic at Calmont Road in the Professional Development League.
The 19-year-old's deflected strike 11 minutes into the second half proved enough for the three points, with The Lions remaining within touching distance of table-toppers Ipswich Town in the Professional Development League.
The first half was largely a cagey affair, with the best chance coming when Mason Saunders-Henry's header from an exquisite Joe Wicks delivery was saved by Ashley Maynard-Brewer in The Addicks' goal.
A physical encounter approached the break with the two sides all square, with the defences coming out on top.
The second half began much the same, but when Saunders-Henry drew a foul 25 yards from goal after some neat play, the opportunity arose for The Lions to pounce.
White stepped up and struck a well-hit strike, which deflected just out of the reach of Maynard-Brewer and into the right-hand corner.
Jason Euell's Charlton side refused to go down without a fight, and enjoyed a subsequent spell of dominance in the Millwall half. Brendan Sarpong-Wiredu spurned the biggest chance for the visitors as he fired over Mark Marshall's ball-in, with substitute Terrique Anderson next to go close with a low strike arrowing just wide of Jordan Archer's goal.
Archer and his defence however looked impressively organised in large parts of the match, and saw the game out with a fine clean sheet and three points.
Next up for Nugent's side is a clash on Friday 12th October at The Den, against a Watford outfit without a League win so far this campaign.
Millwall: Archer, Brown, McNamara, Hanson, Debrah, Stojsavljevic, Harvey (Parker 85'), Wicks, Olaofe, White, Saunders-Henry. Subs not used: Sandford, Mitchell, Alexander, Duncan.