City suffered their second consecutive defeat in the Premier League after they went down to Spurs at White Hart Lane on Saturday.
With the absence of Vincent Kompany and Eliaquim Mangala, Argentine pair Otamendi and Demichelis were handed a start on the day and the duo's poor performance at the back contributed to City's loss.
However, City boss Pellegrini is refusing to point fingers at the direction of the duo and has stated that rather than poor defending, it was questionable refereeing decisions which cost his side against Tottenham.
Pellegrini said: "I don't think that.
"I think they both played very well. The goals were two offsides and set-pieces. Not a problem with the way they played."