Chris Coleman believes Liverpool loanee Ovie Ejaria was a huge miss in Sunderland's midfield in the 2-0 defeat to Brentford.
Ejaria missed the game after suffering a knock in training following a kick on his leg and Sunderland missed his calmness on the ball, says Coleman.
The Sunderland boss hit out at the "erratic" and "nervous" play from his side, with Brentford controlling the game from kick-off.
"The thing that bothers me, we train Monday to Friday and we train well," said Coleman.
"We train a certain way and play a certain way then when the bell rings we play a slightly different way - that's what really bothers me.
"That is what I get annoyed at, but I have to look at us and where we are and the opposition we are up against and maybe the type of characters we need in the team.
"Maybe I need to change certain things, take away all the emotion, look at the game, there probably wasn't a lot in it but we never looked like we had that belief we were going to score.
"When they got in our last third there was an edginess that they are going to get a third, it was there, I can't deny that.
"We are missing Ovie Ejaria, someone who can put his foot on the ball and calm things down we were so nervous in possession, so erratic from the kick off, we are slashing at it, heading balls when we should be chesting it down and passing it.
"That is nerves and panic and you are not going to progress with that. Second half we started passing it and we looked better but we are 2-0 down then.
"It has been a theme for three or four games."
Sunderland switched to a flat-back four for the visit of Brentford, with Bryan Oviedo surprisingly dropped from the matchday squad. Chelsea loanee Jake Clarke-Salter, a natural centre back, was pushed out wide to the left-back slot instead.
Oviedo, the club's usual first choice left-back, was subbed on the hour mark at Ashton Gate a week ago and he didn't make the squad against Brentford, with Coleman saying it was a "tactical choice".
Kazenga LuaLua picked up an ankle injury in training on Friday and is a major doubt for Tuesday night's trip to Bolton Wanderers.
Coleman added: "LuaLua was injured in training on Friday. Bryan wasn't injured, that was a tactical choice.
"I don't think Kaz will make Tuesday, he had a crack on his ankle. He has been struggling with it anyway, I don't think he will make Tuesday.
"Ovie we don't know, maybe another 24-hours if it settles down he has got a chance."
Brentford, 10th in the Championship, are five points from a play-off spot.
Coleman praised the job Dean Smith is doing but doesn't think they will get promoted.
"They have done well, have a model the way they work," said Coleman.
"They are a good footballing team, Dean is a good manager. If you look at them they are a well-oiled Championship team.
"I don't think they'll ever get promoted, I could be wrong, it is so tough because they don't have the finances but if they keep doing what they are doing then I don't think they will get relegated either.
"For Brentford to be where they are, I think Dean is doing a really good job and they are a good outfit."