Dean Holden spoke to Charlton TV after the Addicks lost 3-1 at Oxford United.
A second-half goal from Miles Leaburn and an increased attacking threat gave the Addicks hope before Gatlin O’Donkor’s goal eight minutes from the end of the game sealed a 3-1 win for the U’s.
Holden said: “It’s a first half to address, not forget. We need to do that quickly before the Portsmouth game.
“It was unacceptable in that first half. The players were made well aware of that at half time. We didn’t win enough duels, nowhere near. There were poor goals conceded defensively. We were getting pulled all over the place. The pitch became really big for us and we didn’t pass the ball. We had opportunities to play, we didn’t take the opportunities. We brought problems to our front door and had work to do at half time.
“No doubt we saw a reaction in that second half. Jes [Rak-Sakyi], Corey [Blackett-Taylor] and Miles, in particular, came on and really took the game to the Oxford back line. That’s where we got the goal from, a brilliant run from Corey on the outside. It was good movement from Miles and a fantastic header.
”Then we have a big chance to get 2-2, like we did against Peterborough, and we couldn’t quite take it. The game gets stretched again, they get us a little bit late in the second half with another poor goal from us.
“I made a point on day one of sitting the players down and making a ‘no excuse’ culture. I said we all have to look in the mirror, we can’t just brush it off. We can’t go blaming other people, we have to own it, we have to look at where it went wrong in that first half.
“We knew what we were walking into in terms of where the squad is at and how unbalanced it is.
“Chinny [Richard Chin] comes off with blurred vision and we’re bringing young Tyreece Campbell on in a position he’s not really played before.
“Sess [Steven Sessegnon] has got a bit of swelling in his knee, so he wasn’t fit enough for this one. We have to look at where we are at in the next couple of games and go again.”