City hope to go into 2018 looking to set new standards for Premier League points and goals scored after winning 19 of their first 20 games.
Their current 18-match winning streak is a new record – and can be extended at Crystal Palace on Sunday.
Koeman said: “Of course, people will argue that he is getting the opportunity to do well at Manchester City because of the club's funds.
“But those funds have also been available to a couple of other managers over the past few years in the Premier League – and none of them produced football at such a high level and as entertaining as Guardiola.
“We all know the managers who won trophies, but completely failed to entertain the fans.
“The football that Guardiola is giving us is fantastic to watch – and he is successful. I have to underline that what he is doing is the most difficult way of being successful in football.
“People think he has copied Barcelona, but this style of football is far more Guardiola's own DNA."