User blog comment:B214/Volume 22 spoilers/@comment-83.27.153.180-20160721081322/@comment-9595671-20160722034649

Rias Vs Sona was a prime example of winning but their rating taking a hit, their rating lowered due to how Sona's strategies played out.

So winning is only one part of a Rating Game, it's how you play the game and how you react to the opponents you face that plays a part. So ultimately, the Rating is the staple point.