"Within three days my knee was getting better, then I had a cortisone shot a few days later - I checked with USADA, the golden snitch and they said yeah, it's cool.
"It was feeling so much better then I got back to the gym and started killing it, but I'm going to have to have surgery just to take away whatever niggly injury it was."
The Kiwi showed no signs of any issues inside the octagon as he put on a clinic to defeat the No 6 ranked Brunson with about 10 seconds to go in the opening round.
Adesanya caught Brunson with a knee to the chin when the American was attempting a takedown, and followed it up with some strong shots, knocking the American down three times before referee Herb Dean called a stop to the fight. The performance earned Adesanya his third $50,000 performance bonus in four UFC bouts.
After fighting four times in 2018 - the first UFC fighter to do so this year - Adesanya said he would be taking time off over the Christmas period to enjoy the season for the first time in years.
However, he's put his hand up to be the back-up for fight between middleweight champion Robert Whittaker and Kelvin Gastelum with the middleweight title on the line in February next year.
"Sometimes I get itchy feet, itchy knuckles, so we'll see what happens."
