Adesanya questioned whether Costa has been drug tested in the build-up to their UFC middleweight title showdown on September 26.
He claimed the undefeated Brazilian fighter is "juiced to the f**king gills" ahead of their highly-anticipated clash.
Costa has since hit back at the UFC champion on social media.
On Twitter, he wrote: "Unfortunately to you RUNNERSANYA USADA never came to test me in Brasil. F**k you re already dead men /skull. KoB is coming to you."
Unfortunately to you RUNNERSANYA USADA never came to test me in Brasil :flag_br:.- Paulo Costa ( Borrachinha ) (@BorrachinhaMMA) August 25, 2020
Fuck you re already dead men /skull :skull:
KoB is coming to you https://t.co/SgIEn9qqAt
The New Zealander pulled no punches on Costa as he accused him of cheating.
Speaking at a pre-fight virtual media day, he said: "I think it's great for me, it's that aesthetic of it, I'm this skinny person, this little frail kid that everyone looks at.
"And he looks like the perfect antagonist, he's big, bulky and juiced up to the f**king gills.
"He's a guy that beats everybody on the fence, so when I come out there with the Bruce Lee sh*t and f**k him up, it's going to be 'oh my god wow, he beat that big muscle boy.'"
.@stylebender reveals he asked Paulo Costa about how many times he's been tested during their SportsCenter appearance off-camera:- Submission Radio (@SubmissionRadio) August 24, 2020
"He couldn't give me a straight answer, put it that way. And I told him, I got tested twice in the last three weeks." #UFC253 pic.twitter.com/g8XUxoq2mq
In an interview with Submission Radio, he said: "Where's your (USADA) t-shirt? I've been tested over 30 times, or almost 30 times. So where's your t-shirt?
"I know what it's like, and I'm from Lagos City Nigeria, I know what it's like in certain countries where money talks.
"Where, if you flash your gun, people act a certain way. I know what it's like.
"And you've heard stories about Brazil with people running up in gyms to test people, and they're not complying because of certain things, but yeah, I just know what it's like.
"But I don't mind. I just like bringing that up because I want it to be known, because I said on record, I'm gonna pop him before USADA pops him.
"I'm gonna beat him, and then when he gets caught by USADA down the line, (I'll) be like yep, I still whooped his ass even when he was on steroids. That'd make a great story."
Will it deliver? Not long to find out.
Featured Image Credit: Instagram/YouTube
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