I think that rather than watching a suspect defender we're watching a good defender adapt to unfamiliar and challenging instructions. Arteta appears to have asked this kid to go a long way forward and do a lot on the ball.
We know from the analysts when we signed him that his foot speed isn't his strength, but I reckon we'll see more balanced and aware positioning as he settles in. Maybe only after he gets punished a couple of times but then, if he doesn't get punished, who cares?