#2 Jose Aldo
After defeating Chad Mendes for the interim title, the stage was set at UFC 194 for a unification showdown with long-standing featherweight king Jose Aldo.
With their first meeting cancelled just a few weeks out due to an injury to Aldo, another press tour meant the two rivals had been on promotional duties for the best part of a year.
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But although plenty of hours had been spent marketing the fight, McGregor didn't waste much time once the cage door closed. After a couple of tentative shots, Aldo came rushing forward, over-extending on a right hand, which Conor countered, landing a flush left hook that sent the Brazilian tumbling to the mat. A couple of hammer-fists later and that was that.
The featherweight division had a new ruler - for now at least - and Aldo's reign was over. 13 seconds is all it took for McGregor to put an end to 'Scarface's' 11-year unbeaten run.
With fans expecting an all-out war following the bad blood in the build-up, the swift ending left some feeling short-changed. However, the ruthlessness of McGregor's performance was something to behold, and the victory is currently the fastest knockout in UFC tile-fight history.