User blog comment:Xilinoc/Ch. 562 - THE VILLAIN 2 (Mask De Masculine is a Mexican luchador in a German army)/@comment-4026406-20131221213450/@comment-5398287-20131221220255

Firstly, Momo wasn't actually defeated. She just ended up staying out of the fight because Komamura flat-out told her Bambietta would curbstomp her.

Secondly, as I explained in the review above, the progression of things is less of "Kubo sidelining characters" and more of "Renji is more prepared". If you'll recall the preceding fights, Hisagi and Kensei were beaten because they failed to take out James, and Rose was beaten because he took too long to finish off Mask. Renji is doing neither of those things, which is why he's winning. And it's not an issue of power levels being changed, either: Hisagi, Rose, and Kensei, while powerful, are not the massive kind of powerful that some of the other Shinigami are and that some people seem to think they are, whereas Renji just received hugely empowering training from the Royal Guard and thus can dominate Mask.