Raya somehow denied Ollie Watkins from putting Villa ahead early in the second-half.
Arteta said, "I thought that it was a goal. I saw the reaction of the defensive line and there was none because the ball goes on the cross bar and we are all watching the ball and I went 'no please'.
"Then when I see that striker in that position it’s normally a goal. But David’s reaction, it’s unbelievable."
On the threat of Villa's midfield, Arteta added:
"They do that every time they play. Especially the moment if you lose the ball and don’t counter press it and they break the press, they are a team that are really, really dangerous because hey have a lot of legs, they can break the ball and the strikers start to attack between centre back and full back. They are a real threat and we suffered between the spaces."