This image has lots of potential for improvement mainly because you did a lot of good things in camera. I love how the white foam splits the image diagonally and how the surfer is leaning back, which the composition supports nicely. The image is also very sharp and all in all the quality level is high.
As for it's potential I would suggest tweaking this in post some more. If this was a "studio setup" I would suggest getting some fill light on the subject but since it's not you can do this in post especially since this is an advance editing challenge. What I would do here is brighten the sufer a bit selectively using curves or the dodge tool. I'd also add more contrast to this using USM as a local contrast enhancement tool. The color could also be bumped up just a tad also.
Anyway, just some suggestions on how to make this stand out from the pack more. Really a nice capture. Good luck in the challenge.
Good job of stopping the action here. I also want to say bravo on exposing the water properly. The surfer is coming into the image at a nice angle. This works very well, as does the natural line formed by the surf. Good luck in the challenge.