The former Manchester United captain was full of praise for the Spaniard in the wake of Wednesday night's 4-0 Champions League win over Borussia Monchengladbach.
He said on ITV: "I think what was important when he first went in there, the decision to get rid of two or three really important characters from Man City – Hart, Toure – he made the decision, 'you're not for me'.
"He says he's a challenging coach and he doesn't look like he's messing about.
"They're playing with a lot of confidence, he's rotating the squad, the players are playing with a lot of confidence after a decent start.
"I wouldn't like to mess with him."