Adesanya (19-0) will put his belt on the line against the undefeated Brazilian challenger Costa (13-0) at UFC 253 on September 27, in one of the most highly-anticipated fights of the year.
The fight will be the first time in UFC history where two unbeaten fighters will battle for the middleweight title and presents an intriguing matchup between the versatility and precision of Adesanya's striking against the size and power of Costa.
There's also no love lost between the fighters, who have engaged in several verbal spats outside the cage and have long been on each other's radars.
Speaking to the media on Wednesday, Adesanya said he wasn't worried about Costa being the bigger man.
"Me and Costa have been two rising forces in the UFC," he said. "I've been trying to fight him for a while ... and remember when he said he doesn't know who I am? Well you know who I am now.
"I fought at heavyweight in boxing and kickboxing and I will plan on fighting in MMA at heavyweight at some point. But this is martial arts. It's [about] skills. Size makes a difference if you know how to use it and if you allow it to make a difference.
"But they're always surprised when they step across the cage from me and they realise how long I am ... When they feel me in the clinch and they feel my strength, they're always in for a rude awakening."
Adesanya said he's currently in lockdown at the City Kickboxing gym with nine others in his team – with Auckland being at alert Level 3 due to the resurgence of Covid-19 in the community – and that he has enjoyed preparing for his clash with Costa.
"It's had a great impact on my training because I get to just live at the gym," he said. "I spend most of my time at the gym anyway but now I get to sleep at the gym.
"It's beautiful because right now we're all together huddled up in lockdown at the gym and this is literally – I can say this for a fact – the best training camp I've been having. Just because we're here at the gym, wake up, train, chill. It's back to the simple life.
"Even if this lockdown ended on Sunday or last Friday, I would have still taken the three days being here as a refresher because you sometimes need a refresher or a reset. And being here has done that for me because I have f*** all to do outside of this."
Joining Adesanya at UFC 253 will be three of his Auckland City Kickboxing teammates Kai Kara-France, Brad Riddell and Shane Young who were today announced to be on the card in September.
The 31-year-old Kiwi says he's proud of his team and the progress New Zealand MMA has made over the years.
"I'm very proud of us," he said. "Being here with the team, locking down with my crew ... has just strengthened the bond between me and my comrades, me and my brothers. I love the vibe where we are right now. It's a whole vibe.
"The sport's growing rapidly, constantly. So much is happening that we keep even having to look at new options because the gym is getting packed every day, even after the first lockdown."
In an echo of his speech after claiming the sportsman of the year title at the Halberg Awards earlier this year, Adesanya talked up MMA as the "biggest sport in the world".
"MMA is the biggest sport in the world – people just don't know it yet. Understand that. There's football and soccer, blah blah blah, but all those people watch us because we all know what we're trying to do: we're trying to be the baddest mother f***ers around.
"So whether you kick a ball into a net, dunk a ball, or you charge at another man, [when] you fight, people watch. That's in our DNA."
When asked if he thought his sport could one day eclipse rugby in New Zealand, Adesanya said he's already bigger than the All Blacks internationally.
"I don't really care to be honest. But I know if you put it on the world stage, me myself as Israel Adesanya 'The Last Stylebender' I'm bigger than the All Blacks, like worldwide.
"Not definitely in New Zealand ... but yes worldwide, all around the world, all across the land, I definitely have more footprint than the All Blacks."
