Against Romero (13-4; 9-3 UFC), he meets a wily and experienced campaigner who has shown he's willing to pull out "veteran moves" to help his chances.
The 42-year old, who claimed a silver medal in freestyle wrestling at the 2000 Olympic Games, has made a name for himself as one of the most damaging fighters in the middleweight division. In his nine UFC wins, seven have come by stoppage.
The bout will be the second time Adesanya defends the belt he won against American Kelvin Gastelum last April — with the bout against Whittaker unifying the interim and full-time title. Gastelum gave Adesanya the biggest test of his mixed martial arts career to date, and Adesanya said that fight taught him a lot about himself.
"I learnt where I can go to. I learnt the power of my mind. Romero — I've seen him quit," Adesanya said.
"Seeing him cheat — grab the inside of the gloves, grabbing the fence — they call these veteran moves. I've played against one of the best and most crafty veterans in Anderson Silva. It doesn't work on me, I'm too clued on to it. This guy's a tough test, but I've seen it before."
In the fight against Gastelum, the American found success rushing Adesanya and putting pressure on him from the outset, which could be a tactic Romero tries. However, Romero's stamina has been an area of concern for the Cuban in the past, even in three-round fights, so stepping up to a five-round championship bout will pose a lot of questions of the challenger on top of those presented by Adesanya's unique and shifty style.
"If he tries to do what Gastelum did and rush me or if he wants to play safe and keep a distance — feel free. But whatever he's doing, I know I've got way more in the tank than him; substantially more.
"I feel great. You can put a bet on who gets tired first. I'll bet my whole purse — I know who is getting tired first."