City have suffered from a dip in form that has left them eight points behind Premier League leaders Arsenal but Guardiola has dismissed claims that his players have a psychological issue.
The Spanish coach said: "People wonder why City are not top of the league, but it happens.
"There is a team who has been fantastic so far and this is not a problem, it is accepted that the other team is better, but what do we have to do?
"The only way, is not waiting what they are going to do, try to win our games and play even better. I do not think it is about mentality because you see the game against United and the previous one against Chelsea (a 1-0 win). We did really, really well."
Guardiola takes personal responsibility when City suffer a bad result and knows that he needs to inspire his players to chase down the points deficit.
He said: "We always had belief. When we lose a game, the tendency is always to say we don't run, the tendency is the mentality, or there is no fight. But maybe there is a tactical reason where I did not help them. I have to find something to help the team to get better because I am the man responsible.
"People do not wait, they expect me to find a way to win games. Otherwise, it's 'Pep Out', this is how our jobs work and I want 'Pep In' and to stay here."