Glyn Hodges said that the players failed to heed his half-time warning that Charlton would hit back and they paid the price in the second-half.
Speaking after the 5-2 defeat, Glyn said: "I just thought that we weren't prepared for the second-half. I tried to warn them: you are not going to come to Charlton for a fierce London derby against a side relegated from the Championship, and expect an easy 45 minutes. After they got their two goals in quick succession the writing was on the wall. We didn't acquit ourselves and we folded too easily.
"Of course, it's a concern. It's another occasion when we were in a winning position. You can't put old heads on young shoulders and we have to learn from this. They are a young side and they need leadership out there, particularly at the key times. Key decisions are not being made, and we got punished for the mistakes.
"There is stuff we set out to do, and we didn't do it. Passing from A to B, we didn't even do that well, and it caused us so many problems in the second-half. The writing was on the wall."
Our manager said that he will be working hard with his squad to come back stronger in the coming weeks after today's setback.
"Christmas is coming up and there are no easy games," added Glyn. "It was the first time we had played in front of fans, it was something completely different. We just have to trust what we are doing and have a bit more belief. Sometimes I think they are better players than they actually are. It's a mental thing, and we will keep working on it.
"It's about working everywhere, including on the training ground and with analysis. The boys can pick the bones out of their own performances and what they can do better. We will keep working as a group, it was a bad day at the office, and we will keep moving forward."
The picture above (taken by Matt Redman, Pro Sports Images) shows Dan Csoka celebrating his first goal for Wimbledon and his first goal in the English Football League.
You can see the full post-match reaction below, via the video link to our official club YouTube channel.