Mata was impressed by Villa's win at Arsenal.
"We knew they were a very good team already," Mata told chelseafc.com. "I remember the last game we played against them at Villa Park, which was very difficult. They scored first with Christian Benteke, and there were a lot of rumours about him but he stayed there and is a very important player for them. They're a very compact team, very young and fresh so it will be a tough game for us for sure."
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