It was just last chapter her ability was explained. Stop time for 5 seconds, or turn back time by 5 seconds. Yeah, it's essentially The World and Mandom rolled into one, except Ringo's watch is replaced with a pose.
@neorasp our gal mentioned that her sister gets tired when she uses her ability due to its strenght, so she noticed she got a bit tired and concluded she returned time.
@gigagiga
This isn't like YuYu Hakusho or Hero Academia.
It isn't a weekly manga
I think it's fine to have tournament arcs early especially when this one's small. It's basically 3v3 and only one fight matters to a character's development. I wouldn't be surprised if they skip the other fights or something stupid happens and cuts the tournament short.
Man the author sure can draw, the art is very pleasing and no I'm not talking about the nude part but everything as a whole. Does he has a pixiv account?