Manchester United manager Louis van Gaal believes Leicester are serious Premier League title contenders.
Leaders Leicester are one point ahead of second-placed United ahead of the meeting between the two sides at the King Power Stadium on Saturday.
The bookmakers do not expect the Foxes to remain there for the rest of the campaign but Van Gaal believes there is a chance they could lift the trophy.
"It is possible, I think," the United manager said when asked if Claudio Ranieri's team could win the league.
Van Gaal added: "Normally these kind of clubs can be a long time competing, but at the end it's more difficult.
"But in England because of the quality of the teams, because every team has the money to buy players - and they have bought players - the difference in the Premier League between the clubs in level is not so high."
United must stop the free-scoring Jamie Vardy if they are to move ahead of Leicester and top the table.
Vardy was playing non-league football three-and-a-half years ago, but he is now the top marksman in the country.
The former Fleetwood Town player last week equalled Ruud van Nistelrooy's Premier League record of scoring in 10 consecutive matches.
Last year against United he scored and had a hand in all five of Leicester's goals in the eight-goal thriller at the King Power Stadium.
Van Gaal described Vardy as a "nasty" and "great" player whom he also likened to Dennis Bergkamp.
"He was already last season a very nasty player for us," Van Gaal said. "He scored, won a penalty, and now he is scoring 10 games in a row. Then you are a great player.
"I only know for example Dennis Bergkamp as a player who did the same with Ajax. It's not so easy to do that." When asked whether he would consider signing Vardy, Van Gaal gave a terse reply, saying: "That is not your business, I think."
United went 2-0 up at Leicester last season, but ended up throwing the match away due to a combination of poor defending and a controversial penalty given against Rafael for pulling back Vardy after the England striker had forced him off the ball.
Van Gaal admits the 5-3 defeat, which came in his sixth game in charge of United, is a painful one to remember. But he insists United's defence has improved dramatically since last September.
"I don't want to remember that game especially, because of the result but also the way we lost wasn't good," Van Gaal said.
"I think that [now] our defensive organisation is normally the best part of our game and after the match against Leicester, we are proving that we have very good defensive organisation and we have proved that this season more than ever."
United recovered from the defeat at Leicester to qualify for the Champions League last term, but expectations have grown at Old Trafford since.
Despite being second in the table after 13 matches, some United fans are unhappy with the style of football being played under Van Gaal.
Dissenting voices were heard again on Wednesday when United put their Champions League place in jeopardy with a 0-0 draw in their penultimate group game against PSV Eindhoven.
When asked whether he was worried about criticism from supporters, Van Gaal said: "Of course, because the fans have to be happy, you are playing for the fans so you cannot deny that.
"But also you have to see how our opponents are playing against us, and when you see how they play, you know the difficulty of organising against that type of opponent.
"We are still not lucky in finishing the chances. We are creating chances, and when we are not creating, then maybe I am worried.
"But we are not giving much away. That is why we are second in the league and in our Champions League group."
Meanwhile Leicester boss Claudio Ranieri believes Vardy has thrived under the spotlight during his record goal chase.
The focus has been on the red-hot striker and his manager feels the 28-year-old has thrived on the attention.
He said: "I think it's good Jamie has this - maybe all his team-mates will try to help him. But the main idea is the team. After there is Jamie, there is me and everybody - the team.
"I hope for him and (the) fans he gets the record - but sooner or later someone will break the record. I hope for Jamie he does it.”
