Kevin Nugent was disappointed with his side's 2-0 Professional Development League defeat to Wigan Athletic on Tuesday afternoon - and has challenged his side to bounce back in their next fixture.
The Under 23s suffered a loss to The Latics at Calmont Road, but did threaten the Wigan goal through Besart Topalloj's shot, which hit the crossbar, and George Alexander's penalty, which was saved by Bobby Jones.
After three straight wins, the boss picked apart his team's performance by telling millwallfc.co.uk: "It's obviously very disappointing. We've set better standards than what we've showed today. I was frustrated watching the start of the game from the sidelines - we weren't up to speed and weren't doing the basics which have got us three wins on the bounce.
"After 15-20 minutes I thought we grew into it and dominated the game, certainly until the end of the half, but then we concede a poor goal from an individual error just before half-time.
"However, the lads started the second-half well and if they get something out of hitting the crossbar and the penalty, then it's a different game. As the game went on from there, it was dissapointing. They scored another goal towards the end that we should've done better with as well."
Next up is the visit of Steve Morison's Cardiff City side, and Nugent has challenged his squad to "step back up" against The Bluebirds.
"It's a big game for us next week now. These lads have got to learn and make sure they're able to step back up to their normal level after a below-par performance."