Hmm, The stats are pretty damn close in even catagories, with no huge discrepencies in one or two places even. Rhythm has speed, and the stamina to back it, and a tiny leg in fighting skill, Jay has Smarts and a good will to win, and a tiny leg in air bending ranged ability.
Keeping in mind Jay sheilds with Air, and Rhythm shileds with a shield, I see this as a very non-lethal defensive skill fight. The pushing and blocking will be tiny between rounds of lots of punching. With the same strength and durability, it comes down to agility versus will, and while Jay may get a boost to that will between rounds with air pushery and renewed will, I see Rhythm as doing a superior job DURING the beatery and eventually wearing Jay down.
My vote says Rhythm.