Arsenal boss Unai Emery is convinced by the ambition of new signing David Luiz.

The pair have worked together before at PSG, and Emery thinks the former Chelsea defende will be a major asset.

"We worked for two months together at PSG and then after three matches, the club and he decided to sign for Chelsea," he said.

"Now is the same. It's a very good and big opportunity for us and also the fact that he decided to change Chelsea for Arsenal is an important step.

"He wants to do something important with us, to help us do something important in the present, in the future.

"He has experience, he has quality in the build-up and he's a good defender. He's coming here to help us with his capacity and quality."