Arteta played for Moyes at Everton.
"We hope the fact all the other top teams have changed their boss will help us this season. When you bring in a new coach, you need time to adapt.
"But I still think United will be a big threat.
"I worked with David Moyes at Everton for many years and he's a very clever man.
"He knows he's working with players who have been really successful so I don't think he's suddenly going to make too many changes. He doesn't need to."