Suggested by Destroyer Buster is always a dependable guy and I’m sure he will take the loss here well. He’s got no hope against a pony with the level of super speed that Rainbow Dash has. She can barrel into him and that’ll knock the wind right out of Buster. I expect he won’t even know what hit him because he probably wouldn’t be able to follow her movements. Super speed also means that the impact of her blows will hurt a lot more so one punch may be all she needs. Rainbow Dash wins.