It was near 11 o’clock on Saturday night. The O2 had long since flushed its 9,500 patrons out into the dark and the smell of stale beer cloaked its corridors, but the evening’s business was far from over.

It is 19 months now since Conor McGregor last fought in Dublin, and it is an evening worth revisiting as he returns to the Octagon tonight as the headline act in the UFC’s latest Fight Night at the O2.

From the high of his first UFC victory on American soil last Saturday to the low of a serious knee injury - Dublin Conor McGregor has gone through a range of emotions in the last week.