Nigel Pearson's Leicester side were 3-1 adrift in last Sunday's encounter with United at the King Power Stadium, before producing one of the most memorable in comebacks in Premier League history to triumph 5-3.
That win built on a fine start from Leicester, who have transitioned well to the Premier League after being promoted last term and sit seventh with eight points from five matches.
Leicester will now aim to secure a third straight top-flight win when they visit Selhurst Park.
Palace boss Warnock credited the job done by Pearson, but believes Leicester's victory over United can be attributed to the "unusual" results produced by the Premier League and suggested the manner of their 1-0 victory at Stoke City earlier this month tells him more about the challenge his side face.
"I don't look at the Man United game I look at how they beat Stoke, that's more realistic," Warnock said.
"The Man United match was an unusual game you can't take much from that other than they took their chances well.
"I've got a lot of respect for Nigel. He's done a great job."
Leonardo Ulloa has been a big part of Leicester's early success, only Chelsea's Diego Costa can boast more than the Argentinian's Premier League return of five goals.
Fellow striker Jamie Vardy has also impressed and is set to play despite suffering severe cramp against United, meaning centre-back Matthew Upson (foot) is likely to remain Leicester's only enforced absentee.
Pearson has received many plaudits for his role in Leicester's start, but the former Hull City boss remains keen to hail the collective work of his backroom team.
"You know how much I value the staff I work with, I don't see it being anything other than a team effort," he told the club's official website.
"Clearly it does help if you’ve got talented individuals but they can only shine if you have a collective ethic and common goals."
Palace, who are 15th, have once again proved to be no pushovers in the top flight and they are unbeaten in three Premier League matches since Warnock returned for a second spell as manager last month.
Their last top-flight encounter ended in an impressive 3-2 victory at Everton last Sunday and Warnock confirmed Palace are likely to revert to type against Leicester after an experimental XI was knocked out of the League Cup in extra time by Newcastle United on Wednesday.
In a further boost, Marouane Chamakh is back in Palace's squad after he missed the club's last four competitive matches with a hamstring injury.
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