The midfielder put in an impressive display in the team’s 0-0 Champions League draw with Juventus on Wednesday.
The 25-year-old Frenchman was a regular last season but had knee surgery in February.
Emery said post-game: "He’s very important. He has come back. He goes as a six number.
“He’s giving us a lot of balance, he progressed a lot last year before his injury, playing and with confidence in the build-up.
“He is helping us in this direction. He has a big potential to continue exploiting."
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