He's faltering. Is it because he's losing or because of the legs? Hard to tell.

"Pickpocket-- help flip her over. It's not fair if she can't fight back."

Not that he's particularly intense about honor or fairness, but this is a friendly battle for a friendly purpose so it matters here more than it would elsewhere. Here, he doesn't really care about winning. If Maurice were Misty things would be very different.

Pickpocket floats over and delicately nudges against Grubbin's side, trying to help flip her back onto those little legs.