Chelsea boss Roberto di Matteo admits the arrival of Robin van Persie has made Manchester United stronger.

United are at Chelsea tonight.

"He's been a very good signing for them and has scored some vital goals already," the Italian assessed. "They had a very good start, they recovered from their first defeat in the first game and are a strong team. They were at the top last season and they have added to it, so you wouldn't expect them to be anywhere else."