"Beckham is tremendous," Arteta told the London Evening Standard. "The changes he made, in different countries and different cultures as well, that is tiring, moving your family from one side to the other.
"When people criticised him when he played for Paris St-Germain against Barcelona, I could not believe it.
"What he is doing is absolutely fantastic. He trained with us in January and to see how professional he is was unbelievable.
"I talked to him and everybody who talks about him says the same. He wants to get better and better."