Manchester City boss Manuel Pellegrini was disappointed after his side crashed out of the League Cup.
A below-par City side were second best to Newcastle United as Rolando Aarons opened the scoring after only six minutes and with Moussa Sissoko sealing victory late in the second half.
And with the Citizens hosting Manchester United next Sunday, Pellegrini admits there is room for concern ahead of the derby.
"Of course it's a concern because it is twice in one week we have conceded too many goals and I don't think that we are scoring the chances that we have we don't score, which makes them a little bit nervous," Pellegrini said after the defeat.
"We did not play well. We didn't move the ball in the way we normally do and we were conceding goals too easily and we did not score the chances that we had.
"[But] I'm sure that we will leave this week behind us and carry on thinking about the future.
"David [Silva] has a problem in his knee, we will see tomorrow how big is it. Yaya [Toure] was with some problem in his groin, but I think that's nothing important."
