"It is the first time for a long time at Upton Park that we are extremely disappointed with the result and the manner of how the game went," he says.
"That was the first performance since I have returned to the club where it has gone like that at Upton Park; the shape of the game just didn't go our way and we gave away goals at dreadful times.
"We couldn't retrieve it and it is the first time in a year something like that has happened at our place.
"This league is a tough one and you can't give people goals; both the goals were poor defensive goals.
"Ones like the one Henry scored against us last week are goals you can do very little about, but on Saturday they were poor - and it put our backs against the wall.
"Set pieces and the individual picking up of markers, getting the second ball - Charlton were excellent at it and you have to give them credit for that; they were all over us like hounds.
"There was plenty of effort to get a goal which would let us back in but we just couldn't create too much, although there were a number of half chances.
"That said, they didn't create too much so the game became stalemate, it was going their way, and they sat back and defended.
"It is not often that happens and it is just wasn't there for us, but we have talked about it and it is up to us as a group of people to maintain a level of performance, if we want to be successful in this league."
Paul says that a big improvement is needed, adding:
"We have had three performances and, out of those, there are two we are not pleased with, because they have not been up to standard."
With West Ham bottom of the league - a place occupied this time last season - the focus is on the club, but Paul dismisses any notion of a crisis out of hand.
"People will always look at the league table, so have I, and it doesn't look too clever, but the season is a marathon," he insists.
He does feel, however, that the players' intense pride will turn things around, and he adds:
"Everyone was hurt in the dressing room after the game; hopefully that hurt will kick in and we will rebound."
He says that there was plenty of discussion after the match about what went wrong, and he adds:
"Players have had their say, but that is what the dressing room is for, and it is our jobs to sort it out.
"Plenty of things have been said in all directions and we are ready to work towards getting a result in the next game."
Paul says that Joe Cole did his England chances no harm in front of Sven-Goran Eriksson on Saturday, despite the defeat, and adds:
"I thought Joe looked very lively with a number of efforts on goal and he did himself some good, but the game was disappointing all round.
"We have got to get back to the good home performances and we have to improve away from home as well; the players know all that and so do we - and we will."
With a large number of the squad away, and the reserves having played on Monday, the remaining players had a day off on Tuesday, though they were in on Sunday.
But training is being stepped up again for the rest of the week, and Paul says:
"We will work hard but the fact that internationals are away means it is a little bit disjointed.
"It is now about how we bounce back, and that is very important."