User blog comment:AYET/Let's Discuss Chapter 733/@comment-9358194-20131227022907

The winner isn't Rebecca. She is the Sugar's nemesis because she is able to dodge almost any touch and to knock down quickly. So story-wise she must be dropped into the Scrap for reaching Sugar. That's the reason she need be defeated. And it will give us a little family drama between her and Riku. Oda's rationale!