@Rooster
Midara was just saying it.
To challenge another referee a ranking battle, a challenger has to drop his handkerchief on the ground, and his opponent has to drop his and cover the challenger's handkerchief to accept the battle.(you can refuse it by not dropping your handkerchief)
Midara and Mitora didn't do that, so it's not a ranking battle.
@Lithe
Kiruma is talking about Makuro and Mitora, they had a ranking battle before Mitora went to the TV station and fought with Midara.
Mitora defeated Makuro, who was no.8, and took over his no.8 position.