The Latics claimed a surprise 1-0 victory over City at Wembley in May thanks to Ben Watson's late header.
However, there have been major changes at both clubs since then with Pellegrini taking over the City reins from Roberto Mancini, while former City striker Uwe Rosler is now in charge at Wigan following Owen Coyle's short reign as Roberto Martinez's replacement.
Asked if he had seen a re-run of last year's final, Pellegrini said: "Yes, I watched that, but at the beginning of the season.
"I think now it's a different moment. There are different managers, different players for both teams. You can't link one with another.
"It happened 10 months ago and is not a lesson I can learn in this moment.
"We also played against them at the beginning of the Capital One Cup (and won 5-0) but today it is a different team.
"I have watched the last four games of Wigan and they played very well."
A win for City will book another trip to Wembley as they seek more silverware after beating Sunderland in the Capital One Cup final last weekend.
Pellegrini added: "I enjoy winning titles everywhere but to win titles at Wembley made it special.
"All the players know if we win on Sunday we are in a semi-final at Wembley.
"We try to play every competition with no priority and I think it will be very good for the team to reach the semi-final."
Rosler is likely to receive a good reception from the City fans after scoring 64 goals in 176 games for the club during a period in which they were relegated two divisions.
Pellegrini said: "I know he has an important link with this club but now he is the manager of Wigan and he will want to win.
"Maybe it is not a usual match because of this but I am sure that we are just thinking of winning this match and not all the other things outside."