John Kavanagh has suggested that Conor McGregor's performance tonight was the best of his career.
McGregor's coach tweeted shortly after the bout: "Best version. So far."
The Notorious knocked Cowboy out just 40 seconds into their main event bout.
He floored him with a thunderous left kick before unloading a number of savage punches.
The result means McGregor has become the first person in the history of the UFC have recorded knockout wins at featherweight, lightweight and welterweight.
McGregor vowed to knock Cowboy out before the fight and stated he wanted to "acquire rounds".
He got one half of what he wished for by absolutely annihilating the MMA veteran.
McGregor looks set to stay fighting at welterweight and he says he doesn't care who he faces next as the 170lbs champion Kamaru Usman and Jorge Masvidal looked on.
Speaking after the fight, McGregor said: "I'm going to party tonight, celebrate, spend time with my family and then get back in the gym and train.
"And anyone of these little mouthy fools can get it."
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