Fresh from their League Cup final win over Liverpool, Manchester City turned in a poor display at Anfield as goals from Adam Lallana, James Milner and Roberto Firmino sealed a 3-0 win.
City managed just four shots in the contest and ran 106km compared to Liverpool's 115km.
"From the beginning I could see the team was not recovered from the last week," Pellegrini, 62, said. "We played in the Champions League and League Cup final.
"I am not thinking about the title and not thinking not to qualify for the Champions League.
"I said always the team that wins title will be less than 80 points but I am not thinking about the title but to recover our performance."
Match of the Day pundit Danny Murphy: "City were sloppy. They did look tired. They have players who are so technically gifted but they looked like they weren't up for it, which when you are chasing the title and playing at Anfield I'm not sure is an excuse. There was a lack of concentration and Fernando was the only player who kept going. The others gave up far too easily. You've got to look at attitude and application."
'Fighting for fourth'
Manchester United boss Louis van Gaal, meanwhile, was in a very jovial mood after a1-0 win over a Watford side,who created the better chances at Old Trafford.
Having seen his team's Champions League chances written off and reportedly come close to the sack, United are now level on points with fourth-placed Manchester City, who have a game in hand but face United on 20 March.
"I have to give big compliments to our players because when it is physical and you can win at an important moment, when all our competitors are losing, it's very important," the Dutchman said.
"That's the Premier League, the difference between clubs is so small, you can lose against every opponent, I think.
"We lost against Sunderland and there was a lot of criticism but that is the strength of the league and now you see we are closer to the fourth position, so now we are fighting for it."
Asked by Match of the Day commentator Steve Wilson what he would say to those who had written off Van Gaal and his team, the United boss replied: "Maybe you were also one of them?" before laughing off into the night.
Match of the Day pundit Danny Murphy: "What's amazing is that considering the negativity surrounding Man U they are level on points now with City. But Watford caused them all sorts of problems and they could have been in big trouble. None of us can predict what's going to happen, that's why we love it so much."