Millwall captain Tony Craig has called on his teammates to learn from their heavy home defeat at the hands of Coventry City.
The Lions wasted a big chance to take the lead from the spot four minutes in, with Lee Gregory's miss proving costly.
Coventry went on to win the contest 4-0 at The Den to leave their opponents stuck on three points from their opening two League One fixtures.
"Losing 4-0 at home is very disappointing because the manner of the first half which we lost it is one of those days where it just seemed everything went wrong," Craig told reporters. "But give Coventry credit, they are a good side, kept the ball very well, have a lot of exciting young players and a lot of very experienced players as well.
"Don't get me wrong, a lot of things went wrong today but you've got to give Coventry credit as well. We had the penalty, the keeper has saved it and after that it has certainly given them a lift. It deflated us a little bit but we've got to learn from this as soon as possible.
"We will go through it and there will be no holding back in training because quite frankly today was just one of those days which wasn't good enough. I've had results like this before. You've got to take them on the chin and move on as quickly as possible."
Millwall have the chance to bounce back in midweek when taking on Barnsley.