The Chilean has a poor record against Chelsea coach Jose Mourinho and has beaten him only once in nine matches in Spain and England.
"I think it'll be a very similar game as we have a style of play that we don't change no matter who we're against," Pellegrini told reporters on Friday, although he did hint at one tactical alteration.
"From the other game we know also that we have to try not to be very open on the counter-attack. And if we play well, there is no reason we cannot beat them.
"We know the way they play, they always play. But I don't think that's the reason we didn't win that game.
"They played very well and we did not play so well and missed three clear options to score. Then they defended very well - and that is no reason to change the way we play."
Mourinho's Real Madrid beat Pellegrini's Malaga five times, drew once and lost once when the two duelled in La Liga and the King's Cup, and Mourinho has won both matches against Pellegrini in the Premier League this season.
Chelsea beat City 2-1 at Stamford Bridge and ended their perfect 11-match winning home streak in the league at the Etihad last week.
Pellegrini's side have scored 115 goals in all competitions this season, but have failed to find the net in their last two games against Chelsea and Norwich City.
Mourinho's tactics in beating City were hailed as a masterclass for the way he nullified the threat posed by midfielder Yaya Toure and hit City on the break to win.
But FA Cup matches are always hard to predict and City are easily capable of repeating last season's 2-1 semi-final success over Chelsea, under coach Rafa Benitez at the time.
City were given an unexpected night off when their league match against Sunderland was postponed because of the weather on Wednesday.
With Chelsea and Arsenal both drawing in midweek, City are well-placed in the league, two points behind leaders Chelsea, and one point adrift of Arsenal with a match in hand.
"You are always talking about Chelsea, Manchester City and Arsenal but this is a very close Premier League with other teams also fighting for the title," Pellegrini said.
"Liverpool is fighting, Tottenham are fighting and Everton so it's not just about three teams."