Villa snapped up Barkley as a free agent after he came off contract at Luton.
"I knew Barkley before but watching him playing at a high level when I was in Spain or other countries," Emery said. "Two years ago, when I came here, he left England to play in France with Nice.
"I was surprised because he was a player - here four or five years ago - but his career hasn’t been consistent. It had been, probably going down.
"Last year, we played Luton at home, here, and we analysed Luton and I was thinking: ‘Wow,’ how he was playing. In my ideas, my spirit, my style as a coach he was completely a player who could play with us.
"Through it, we decided to sign him. And he’s doing exactly the same work I was expecting from him. He’s playing well. I think he can improve. He’s humble, he works hard every day in every training session.
"He’s playing always with the focus we want and he maybe not starting matches but he is playing minutes and when he’s in the starting XI, he’s doing very good work."
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