The Gunners have not mounted a serious title challenge for years and are now down to sixth place in the table, eight points behind Chelsea.
The Blues boss said: "Football has changed since the arrival of people with big money in the Premier League.
"It used to be OK to manage with common sense. To have a good manager like Arsene Wenger was fine and you could achieve things. Now it's a different world because of the clubs with big money.
"You can't compare the game to how it was 10 years ago. I have a good relationship with Arsene. He is one of the best managers in England, if not the very best, for what he has achieved and the way he has done things.
"He has won a lot in his time and that means his club has confidence in him. He did well when he first arrived, the style of football was good and the board and fans were happy with him.
"People talk about him not winning trophies any more, but he is still a great manager doing a great job. He has to keep doing things his way even if it is too difficult.
"Hopefully he will keep doing well for another four years, but not this weekend."