Manchester City coach Pep Guardiola has said England midfielder Jack Grealish has "played much better than maybe he believes" since joining City for £100m.
City face his former club on Wednesday and Guardiola said: "I know how perfect he is. I don't have doubts about that.
"I didn't see one game yet where he did not play with the quality he has."
Grealish remains a doubt for Wednesday's encounter having not featured for City since 3 November due to a minor injury he suffered on England duty.
The Villa academy product has two goals and three assists from his first 15 appearances for the defending Premier League champions.
Guardiola added: "Here I demand they play the best every single game and after we try to analyse the reason we did not play at a good level and we are going to help you. So far Jack Grealish, in the games, always plays good.
"Maybe at Villa, everything started with him and he was free. Now he's in a new position and maybe has not been so determined or so clinical in the final third.
"Maybe because he respects his mates, because it's a new environment. That's normal, it's a process. He needs time. But what he sees and what he has to do, is so easy for him with the quality he has.
"Just be free here and be who you are, that's all, no more. When they get the ball close to the box, you decide whatever you want. That's why you are Jack Grealish and not another player. They have to play and make their moments.
"Sometimes maybe he has to be a more aggressive guy, but the decision making, to make an extra pass, was not wrong. It's good, he creates space for the guy who got the ball from him. But play bad? Absolutely not."
Guardiola says City face player 'emergency'
Guardiola added City are in an "emergency" with just "14 or 15" senior players available for Wednesday's game.
Like Grealish, Phil Foden is also doubtful, while forward Ferran Torres misses out with a foot problem and defender Aymeric Laporte is suspended.
Kevin de Bruyne is yet to resume training despite testing negative after a bout of Covid-19 and the length of midfielder's absence is still not certain.
Coming into the busiest time of the season, when nine Premier League games are crammed into six weeks, Guardiola is concerned.
"We are in an emergency in the squad because we have few, few, few people," he said.
"We never complain when it is not possible for players to play because of injuries or red cards because I trust the squad a lot and other players can come in.
"But we are in real trouble for December - the toughest month of the year. We have just 14 or 15 players. And a lot of players have played a lot of minutes."
With John Stones fit, Guardiola does have 15 senior players available, even without Foden and Grealish.
In addition, youngsters Cole Palmer and James McAtee are expected to be involved at Villa Park.
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