The defending champions and last season's runners-up meet at the Etihad Stadium in the first big match of the new season, with the Chilean fully aware of the game's importance.
City beat Liverpool at home last year, but the return clash at Anfield nearly ended their title hopes.
Pellegrini's men were beaten 3-2 in April, but recovered and remained undefeated in the final six matches to clinch top spot, finishing two points clear of Brendan Rodgers' side.
Both sides recorded victories on the opening weekend of the season and Pellegrini knows it is crucial that City collect all three points in their first home match.
"I always say to the players that these games are games of six points, especially when you play at home with the most important squads of the Premier League such as Liverpool or Arsenal or Chelsea," he told a media conference on Friday.
"It is important for us as we are just starting the season and maybe we don't have our whole squad in the best fitness moment but I think this week we work very hard and very well.
"I hope we can do a very good game and win the three points."
Pellegrini hopes to include Bacary Sagna and Pablo Zabaleta in his squad for the match, but new signing Eliaquim Mangala will not feature as he continues to build-up his fitness.
"Mangala is just starting working with us, so I think that he needs more time to go with our squad," the 60-year-old added.
"All the rest of the squad is fit except [Alvaro] Negredo.
"Sergio [Aguero] needs a long pre-season, that is why he is playing just some minutes during the game but he is available and [Frank] Lampard also.
"Pablo, Bacary Sagna, [Vincent] Kompany, [Martin] Demichelis and Fernandinho, they already played. For this week all of them will be not 100 per cent but ready."
