The Norway international took his goal tally to 42 in 37 matches with his sixth hat-trick of the campaign, which is one more than the total of every other Premier League player combined this season.
Haaland has scored more trebles at home this term (six) than he has had matches in which he has failed to find the net (five) and has registered nine goals in eight days after netting five in the midweek Champions League win over RB Leipzig following his winner at Crystal Palace.
"I have played against the greats of this time, (Lionel) Messi, Ronaldinho, (Zinedine) Zidane, Cristiano Ronaldo," said the former City defender and captain.
"In the end they are part of a very special elite because I think even the very best find it very difficult to stop those guys, no matter what you say, because they will find a way and someone like Erling will keep finding a way.
"The biggest thing for me is his game can still improve and that is maybe the difference with the other superstars in general, to me he looks like a superstar who is willing to improve and that is exciting to see.
"I think the goalscoring record in general puts you in a certain bracket, a certain category. I don't need to say more than showing you his record of goals.
"That is the hardest part of the game but I see the mindset to improve. His game has improved from when he arrived six months ago and if he continues to do that he is going to have to (be considered a great) as this is not something you experience a lot."
Haaland is now only four goals away from becoming the highest goalscorer for a Premier League club in all competitions in one season.
That record is currently held by former Manchester United striker Ruud van Nistelrooy (2002-03) and Liverpool forward Mohamed Salah (2017-18) but Haaland looks on course to comfortably score 60-plus goals.
Asked if he had set himself a personal target, Haaland told BBC One: "No, I have not.
"I'm a striker, I love to score goals, but my focus is not on scoring goals but on getting the chances. If I get the chances, there's a good chance I'll score."
His hat-trick overshadowed the contributions of Julian Alvarez, who scored twice, and Cole Palmer who found the net minutes after coming off the bench to replace Haaland.
His manager Pep Guardiola joked Haaland's goalscoring record would make things harder for the player in the future as expectations were now so high for him.
"This guy will have a problem in the future, every game he will be expected to score three or four goals and this is not going to happen," said Guardiola.
"He doesn't care because he is so positive, so optimistic, never complains. Julian, again, what a partnership. When they play together they score goals.
"The target numbers (for Haaland), I don't know but if we play good, Erling will score goals. It is incredible he scores goals only playing one hour. So effective, an incredible threat. His joy of life."