Arsenal boss Arsene Wenger is delighted with Calum Chambers' progress this season.
Chambers signed a two-year contract extension in October, tying him to the club until 2021, and Wenger believes Arsenal are reaping the benefits of his year away at Middlesbrough.
“He's done well - he's more mature," Wenger said.
“[Last year at Middlesbrough] he gained the belief that you have the level to play in the Premier League, that you can do it and you get that confidence from your manager for a long period.
“That gives you confidence and from that confidence you can express your qualities. For Calum Chambers, those qualities are immense."
Source: tribalfootball.com