Sam Hatton slotted home a first-half penalty for Welling United as a Millwall XI slipped to a narrow 1-0 win in Monday night's pre-season friendly at Park View Road.
The game proved a useful exercise for The Lions, however, with left-back Joe Martin getting his first pre-season match action under his belt by playing in the first half.
Likewise it was also an opportunity for Fred Onyedinma, Sid Nelson, Alfie Pavey, Gregg Wylde and James Brown, who all featured at some stage for the senior side against Brentford at the weekend, to fine-tune their fitness levels ahead of the League One opener on 6th August.
The home side started brightly and went close to scoring on 14 minutes when Oliver Sprague volleyed narrowly off target.
However just four minutes later Welling made their promising start count. Lions defender Paul Rooney was penalised for a foul on Harry Crawford, who had been picked out by a great forward pass from Danny Waldren, and referee Ian Fissenden had no hesitation in pointing to the spot. Up stepped Hatton to send former Wings' loanee Tom King the wrong way.
It took a sliding tackle from Sid Nelson to avert the danger as Welling pushed for a second goal moments before Crawford broke through once more, but didn't have the angle to beat keeper King.
Millwall eventually conjured up their first real scoring chance with an Onyedinma shot from 20 yards that flew wide of the target.
Operating in a central striking role, Onyedinma twice got in good positions before the break, only to be thwarted by good defending from Mitchell Nelson and keeper Chris Lewington.
Welling went close to adding a second goal seconds after the restart, only for Crawford to fire narrowly wide after the visiting defence had been caught napping and at the other end Alfie Pavey was through on goal, but keeper Lewington was quickly off his line to block.
Pavey was left ruing a glorious opportunity to level when sub Noah Chesmain, a half-time replacement for Martin, whipped over a sumptuous delivery that picked out Pavey to perfection at the far post, but the striker failed to hit the target with his header.
Welling responded and it took a brilliant clearance off the line by right-back Brown to deny Hatton a second goal of the game.
The Lions tried to find a way back into the game and did cause a few anxious moments for the home side as a Kyron Farrell free-kick flew wide and Chesmain volleyed over.
Harry Donovan went agonisingly close to conjuring an injury-time equaliser, only to see his side-footed effort bounce inches wide.
Millwall: King, Brown, Martin (Chesmain, 46mins), Carmichael (White, 75mins), Nelson (Bray, 60mins), Rooney, Twardek, Farrell, Pavey, Onyedinma (Donovan, 60mins), Wylde (Philpot, 46mins). Subs not used: Sandford, McNamara.