The midfielder came off the bench to help City cruise to a 2-0 win against Leicester City.
While they made hard work of the game at first, the Citizens were able to claim a much needed three points on Sunday.
“Oh a lot,” Guardiola said when asked what he liked about the display.
“It’s not a doubt, in the past there are things sometimes in the situation we’re living, I have the feeling ‘okay give the responsibility to the senior players, not the young ones’ but sometimes the senior players have more pressure than the young ones who have nothing to defend and just want to show their space in world football.
“I had the feeling before the game that if I had to make a substitution the first one would be James. I felt it.
“He can play in the wing, pockets, striker, three positions up top and what I was pleased with was every action he did was good.
“He didn’t make one wrong action, in the position we were defensively he grew up a lot in Sheffield, that period made him so, so mature.
“But he’s a player, in a generation we have at City that have been unbelievable, when you see Romeo Lavia, Cole Palmer, Morgan Rogers, Macca, Liam Delap, Taylor Harwood-Bellis, they’re incredible players come from there and he was part of that generation, he captained them.
“That’s why when I said to Txiki, I know it’s unfair to say because you asked to stay and after we didn’t give the minutes that’s fair, that’s right.
“But I always felt this guy could play with us, and I’m very pleased for him because he’s an incredibly lovely guy, trains really good and he wants these minutes.
“It’s simple. All the players, I said many times, you want to add something, on the grid and on the grid Macca today proved it.”