Guardiola brings Bayern, the German and European champions, to the Etihad Stadium in the second round of fixtures in Group D this week.
Pellegrini is still to get the better of the former Barcelona boss, with whom he clashed regularly in Spain.
Barcelona beat Pellegrini's Real Madrid twice during the 2009-10 season, when the Catalans pipped the Bernabeu giants to the title.
With Malaga, Pellegrini lost all four games against Barca between 2010 and 2012. His only inkling of success in a Guardiola battle was a 3-3 draw at the Nou Camp with Villarreal in 2009.
Now in charge at City, Pellegrini has a much more impressive squad at his disposal but his only concern is eking three points out of them and not finally outmanoeuvring Guardiola.
The Chilean said: "It's always about the players. I don't play against Pep Guardiola. It is Bayern against Manchester City.
"The key is always the performance of the important players. They must appear in important games and normally it's the key that makes the difference."
Pellegrini's strong Champions League reputation, having taken Villarreal to the semi-finals and Malaga to the last eight, was one of the chief reasons City recruited him in the summer.
Guardiola, who has won the competition twice as manager, had previously been linked with City but had long been appointed by Bayern when the Eastlands vacancy eventually arose.
Pellegrini said: "Pep is a great manager and he's at a great club also.
"I know it's not easy for him to improve on what Bayern did last year but in some way he will give Bayern the characteristics of the teams he managed, the characteristics that he gave to Barcelona in his four years. We expect that from Bayern."
City are finally hoping to make an impression in the Champions League after premature exits in the past two seasons.
They opened their latest campaign with a comfortable 3-0 win over Czech side Viktoria Plzen but group favourites Bayern - who beat CSKA Moscow 3-0 in their first game - will provide a much sterner test.
Despite facing the champions' fearsome attacking armoury, Pellegrini has no intention of playing safe.
He said: "We never think about a draw. Of course if we cannot win it's better to draw than lose but we're not going to go into the pitch thinking (of) a draw against Bayern.
"From the first minute we will go to win the three points.
"For me it was very important to win the first three points against Viktoria Plzen.
"Now the second thing is to try to win our points at home.
"I know that Bayern is a very strong team but we're also in a good moment and hopefully we can get the three points here."
City have shown recently just how well they can play, notably hammering arch-rivals Manchester United 4-1 in their last home game.
But they came unstuck at Aston Villa on Saturday as they surrendered a 2-1 lead to lose 3-2.
Pellegrini said: "I always expect a big response.
"We started well in the Champions League and it is important for us to continue, beginning at home with the most difficult team of the group.
"We need to play 90 minutes in the best way, knowing every mistake or error we make we can concede a goal.
"We have to play against the last champions of the competition but I'm sure we can do well, exactly as we did in the Premier League against Manchester United.
"The last match we didn't win but I am sure they will play at the (right) level - we know how to do it."
City's response could include Sergio Aguero and David Silva, who are both in contention after injuries.
Striker Aguero was not risked at Villa due to a minor knock while Silva took part in an open training session after five games out with a thigh strain.
Pellegrini said: "David is in the squad list. He can play at least some minutes tomorrow. Sergio is fit and he is also on the list."