He didn't do that great of a job closing out on him. He never stands directly in front of Shoshi (he had a second to do that and he didn't). He has his hands up to the right of Shoshi and then turns (sort of a matador close-out). He might have better altered the shot if he stood his ground directly in front of Shoshi instead moving off to the side of Shoshi. Watch the video (from 1:25:56 to 1:26:10):
Actually, I forgot that they showed a slow-motion replay as well. Watch from 1:26:19 to 1:26:31. Mathias CLEARLY did not stand directly in front of Shoshi. He stood to Shoshi's right (our left from that angle).
It's a moot point, but don't pretend that Mathias made as great of a close-out as possible in that instance.