Good shot, but there are a few minor nitpicks. One being the lack of glass distortion. Some others would be his footing. His feet dont look really steady, and his knees are bowed towards each other. I'd like to see this done with a telephoto, so that it would be more of a mid shot. Then focus on capturing just the fist and facial expression. If you're at a tighter-in crop, you'll bring more focus to the action and really force the viewer in.

That's all just me though. The way you shot this, it looks excellent.