Manchester United striker Zlatan Ibrahimovic admits he is feeling the effects of a hectic first season at Old Trafford.
The Swede has already made 44 appearances this campaign, scoring 28 goals, with United having reached the latter stages of three cup competitions during Jose Mourinho's first season in charge.
Mourinho's side have also been involved in an ongoing scrap for a Champions League place, and head into today's game with Chelsea six points adrift of fourth-place Liverpool with two games in hand.
And Ibrahimovic believes the Premier League leaders have benefited from their lack of European football.
"We have one month to go, it's many games we play," the 35-year-old Swede said in quotes reported by the Daily Telegraph.
"I have been playing almost all the games. But we are still grinding, we are still pushing because we have this Europa League and the end of the Premier League. We fight for it."
Asked about Chelsea, he added: "I think they are a good team.
"Overall a good team and then of course they are playing once a week which makes a difference also because at the end of the season, I don't know how many games we have in total but I think we have much more than them.
"They haven't been playing in Europe this season and they went out from the League Cup early. But they have a great team, or else they would not be number one."
United are unbeaten in the league since a 4-0 thumping in the reverse fixture against Chelsea at Stamford Bridge on October 23, but Ibrahimovic insists that run counts for little.
"I would prefer to be first in the league and not having this record," he added. "It doesn't give us anything, this record."