But the Chilean does not believe it will be a major factor and has warned that his side still have an important job to do at Anfield.
With Chelsea involved in the Capital One Cup final, City can cut the London side's lead at the top of the table to two points with a victory in the noon kick-off on Merseyside.
City should go into the game much fresher, having not played since Tuesday while Liverpool only returned from their Europa League game at Besiktas at approximately 4.30am on Friday.
Pellegrini said: "I think that of course it is an advantage, (but) not a decisive one because I always think the decisive thing is the performance on the day of the game.
"If we think we are going to win that game because Liverpool arrived yesterday night late, that is not the reason.
"But I have played in the Europa League and when you arrive on Friday it is not the best way to prepare for a game on Sunday - but that is the rules
They are playing Europa League.
"Maybe another time we (will) prepare worse for the game."
Pellegrini could open himself up for criticism given that last month his team only returned from a winter training camp in Abu Dhabi the night before their FA Cup loss to Middlesbrough.
But there are differences given that City tried to time their journey to allow optimum rest while Liverpool effectively lost a night's sleep after their match went to penalties and their return flight was delayed.
The disrupted preparation could blunt Liverpool's edge just as they seem to be building momentum for a top-four charge, but Pellegrini is not attaching too much significance to it.
He said: "We must play very good because they also have a strong squad
I don't think they will play the same starting 11 as yesterday night
They are a strong team and it is a difficult stadium."
City were outplayed on Tuesday as they lost the first leg of their Champions League last-16 tie to Barcelona 2-1.
But on the home front they have been much more fluent in their last two games after difficulties early in the new year, beating Stoke and Newcastle 4-1 and 5-0 respectively.
Chelsea remain strong title favourites but City did claw two points back last week and Pellegrini wants to take advantage of their cup distraction this Sunday.
He said: "Of course it is important, and more than psychologically it is important mathematically.
"If we are going to have three points more, we are going to go two points behind Chelsea
It is very important to beat Liverpool and to continue winning in the Premier League, and continue fighting until the end to retain the title
As soon as we close the gap it is better for us."
The defeats of City and Liverpool this week came amid a difficult spell for English sides in Europe
Arsenal and Tottenham were also beaten while Chelsea still face a sizeable task against Paris Saint-Germain to guarantee Champions League progress.
Pellegrini said: "I don't think it is about the level of English football but I think there are a lot of things that maybe are important reasons why the results have happened.
"The Premier League is very strong and every game you must play 95 minutes at 100 per cent intensity
Maybe in other leagues it is not so hard every game.
"In December and January, especially in December, you have to play nine games
Last year we played 18 games in two months
Maybe it is not the best way to prepare for the knockout stages in Europe.
"But there are a lot of things and also this year was not a good performance of the teams."
Source : PA
Source: PA