Rafa Benitez admits he was not happy with his side's mistakes after Newcastle suffered a shock 1-0 defeat against Blackburn on Saturday.
Charlie Mulgrew's second-half strike condemned the Magpies to their first defeat since mid-September, and lifted the visitors out of the Sky Bet Championship relegation zone.
Newcastle's defeat came after Benitez made six changes from the side that had won at Leeds last weekend, and the Spaniard conceded he had perhaps erred with his team selection.
"It was very disappointing because I didn't like the way we started the game or the way the game was stopping all the time with free-kicks and corners," Benitez said.
"I didn't like our reaction when we were losing, and we have to do better. I didn't like the chances we didn't take, and I didn't like my decisions. But we cannot change things. We have to analyse what happened before the next game and make sure we don't make the same mistakes.
"I knew that when you lose a game and you change your players, everyone blames the manager. I knew that. But in the same time, we have to show more character and more personality.
"We didn't control the game the way we have been doing it. If you don't perform at the level you have to perform, you have to give credit to them."