There is little else riding on the contest, with City having guaranteed a place in the last 16 with two games to spare and Plzen yet to pick up a point in the group.
But if results go City's way, they could still supplant reigning champions Bayern Munich at the top of the group and Pellegrini wants to finish the section with a flourish.
The Chilean, whose side beat the Czechs 3-0 in September and are in great goalscoring home form, said: "I think it is very important to win the group.
"It is not the most important thing, the most important thing is to qualify, but I think it is important to be at the top.
"It's also important to play well on Wednesday.
"We are not trying to score five or six goals every match here. The most important thing is to win and then we will see what happens."
Captain Vincent Kompany, Stevan Jovetic, David Silva and Jack Rodwell remain sidelined but Joe Hart will return in goal.
And Pellegrini has ruled out any prospect of a loan move for the England keeper, saying: "Of course he stays. There is no chance that Joe Hart could go out of this squad in January."
Plzen coach Pavel Vrba claims his team will not be fazed by the firepower available to Pellegrini's side, despite their 6-0 thumping of Tottenham on Sunday.
City have scored 18 goals in their last three home games and will be confident of adding more against Plzen but Vrba believes his side have learned from their 5-0 defeat at the hands of Bayern last month.
He said: "We have watched highlights of their games and can see they're a very strong team.
"They've got a busy schedule though, so we're hoping they might not play their strongest side.
"Any game from now on is huge experience for us and we'll be aiming to give them something of a hard time.
"Bayern was quite an experience and I agree with the reporters' views, we didn't play very well.
"The quality of their team, their ability, the situation was all daunting for us, but I think we can draw on that and won't be as overwhelmed."