Not really seeing any strong connection to the rule of thirds here regarding composition but not going to bust your balls for that either, just seems more centrally composed and you would have needed to crop off the top for it to fit more to the challenge.
I like the colors and use of DOF. But how is this 1/3 rule? The head dead smack in the middle of the image?!?!?! Move the head to the bottom right hand of tha image and increase the green background at the top left hand part and it would have been perfect.......