WATCH: Dana White caught in the middle as Adesanya and Costa staredown erupts ahead of UFC 253 headliner

If the build-up to their UFC middleweight title clash had seemed unexpectedly serene, then things exploded into life at Friday's final staredown between Israel Adesanya and Paulo Costa.

Middleweight ruler Adesanya and Brazil's Costa both put their unbeaten records on the line as they headline UFC 253 in Abu Dhabi this weekend, and things got heated ahead of time when they faced off on Friday. 

Costa appeared first on deck and shook hands with UFC boss Dana White with a smile, before Adesanya arrived and also appeared in relaxed mood.

That swiftly changed however when Costa revealed a black judo belt around his waist and then pulled out a white one and tossed it at Adesanya, who responded by flinging it back forcefully.

Dana White appeared momentarily flustered as he was caught in the middle, before the pair were restrained. 

Adesanya then made a sarcastic series of kicks in the air as the fighters traded remarks and Costa again headed menacingly toward him before being pulled back.   

Nigerian-born New Zealander Adesanya had this week dismissed Costa's 13-0 record, saying: "His resume doesn't hold up enough.

"You look at the guys he's beat. He beat an over-the-hill Johny Hendricks, no offense.

"He beat Uriah Hall, who was doing quite well in that fight, one of his better performances. But Uriah Hall succumbed to his will, because Uriah Hall sometimes breaks mentally. And he beat Yoel Romero, who is on the way out, anyway.

"I don't think it's going to be the greatest middleweight fight in history. I kinda already did that with Kelvin Gastelum, so I have that in my back resume," said Adesanya, who puts his own 19-0 record on the line. 

The pair had also clashed over who could lay claim to being the better grappler, with Costa saying: “Before I become a striker I was a grappler. I’m a black belt in jiu-jitsu, my brother’s gym, my coach. I have a lot of knowledge on BJJ. Yes, this fight can be on the ground also.”

Adesanya replied: “No one needs to see your grappling because you suck. You were on TUF on the floor saying, ‘No, I gave my all. I give 100 percent.’ You can’t grapple for sh*t.”

That appears to have set the stage for Friday as their animosity spilled out into the open, whetting fans' appetite for what could be a belter in the octagon in Abu Dhabi.