I'm sorry, but this picture doesn't do anything for me. It's so unclear i can barely tell who is a guy and whos a girl! Try getting it sharper and it would look much better.
Looks like fun!! I like that you kept the ball in the picture, although I would have liked to see more of the facial expressions(which is always the challenge of the candid shot, I think!)
Overall I think it's a neat shot with the interesting colors of the water, etc. I'm not sure it does a lot for me in regard to the challenge though. It may have been more effective to have focused on the expression of an individual player. Better yet, focus on one player and wait for him/her to make a bad shot, and capture their reaction.
I like how blue the water is. The rest of the picture is a little dark though. What film speed did you use to keep the rest that light and keep the ball from blurring.