"I think they've been brilliant for us," he told arsenal.com. "Calum Chambers at the back, at a young age, is playing with so much maturity. To make a big move to a team like Arsenal and to fill in for someone like Per Mertesacker as well as he has done is credit to him.
"Same as Mathieu Debuchy, we know what a good player he is but he hasn't let us down at all since he's been here - he's been outstanding.
"Alexis Sanchez is a great talent and he showed us what he can do out there. I think there's more to come from all of them as they bed into the team and they feel more at home. But they are three brilliant signings and they really are helping us. I'm sure they will for the rest of the season."
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