The Irish superstar took just 13 seconds to defeat his opponent.
It was supposed to be an epic, but it was shortlived.
For those UK fight fans who stayed up until the early hours of morning to watch the fight, they got 13 seconds of action.
McGregor slipped a punch from Aldo before unleashing a devastating counter left to send one of the best ever, pound for pound, crashing to the mat. He carried on his assault, with two hammer blows to the head before the fight was finished - the fastest ever UFC title fight.
McGregor, as always, was backed by a vociferous Irish crowd in Las Vegas and McGregor has now thanked his fans on Instagram for the boost their support has given him:
Thank you for all the kind messages! I am extremely grateful and proud to be in the position I am in. To the naked eye it was 13 seconds, but to my team and my family it has been a lifetime of work to get to that 13 seconds. Congratulations to the staff at the UFC on a historic week in the sports history and an amazing 2015 for the company. It is an honor to be playing a part in this great companies continued growth and success and an honor to top off a phenomenal week in the sports history. Thank you to all the fans who travelled and made this week what it was!! The traveling Irish are untouchable when it comes to creating the atmosphere needed to make a week like this what it was!! I am forever blown away by the support of my country. We have changed the game forever!!! Respect to a great champion in Jose Aldo. The true greats will always overcome adversity. I wish him and his loyal team well on their journey back. Much respect. Thank you all!!!
He said he would do it, but doubters suggested that the experienced Aldo would just have too much for him.
Instead, McGregor made it clear that right now, he is the biggest star in Mixed Martial Arts.