#4 UFC 194 (1.4 million buys)

It hasn't happened many times in his career but Conor McGregor entered UFC 194 as the underdog.
The reason? His opponent was Jose Aldo. Aldo had only tasted defeat once in his entire career, a full decade earlier. Since that point, the Brazilian had smashed through everyone put in his path and successfully defended the Featherweight strap a record seven times in succession.
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That all ended in double quick time when he stepped into the Octagon with "Notorious."
It took just 13 seconds for McGregor to wreck Aldo's fearsome reputation after he marched towards the champion and smashed him with a huge left hook that floored Aldo.
With that, McGregor announced himself as the poster boy of UFC and the company's biggest star.
The 1.4 million buys was just the start for McGregor's incredible run as MMA's biggest drawing card.