Could not guess?

from Yandex News
Klitschko clashed with Chisora in a nightclub in Ibiza
According to the newspaper, the Englishman provoked the Ukrainian to fight with his remarks in his address. The guard quickly responded to the fight and stopped it.
How, fucking, the guard stopped the fight of two superheavy?! to

Like any "bull" from the knee / thigh between the legs, then either face to knee, or thigh to thigh.
Pavlik has been a nightclub security guard for 8 years.