‘The Last Stylebender’ put on a dazzling display to overpower Costa on Fight Island, culminating with a lightning-quick counter combination to drop the Brazilian before finishing him with a ground-and-pound barrage at 3 minutes and 59 seconds of round two.
Adesanya kept his title and unblemished record in tact as he picked up a 20th professional MMA win, while Costa’s own perfect record was ended in devastating fashion as he lost for the first time in what was his 14th contest.
The bad blood between the two had simmered in the build-up to the fight, including when tempers flared at Friday’s staredown when Costa had tossed a white judo belt at his rival in a show of contempt for his grappling skills.
But it was the Last Stylebender who had the last word in Abu Dhabi, and the Nigerian-born New Zealander made his apparent lack of respect for his opponent clear as soon as referee Jason Herzog had waved off the fight.
As Costa remained curled up in a ball and in a daze on the canvas, Adesanya thrusted at him from behind, leaving MMA fans in no doubt as to what the gesture meant.
“This man is soo disrespectful. Look at how Israel Adesanya air humps dude after he knocked him out,” wrote one fan, adding a laughing emoji.
“He literally f*cked Costa,” wrote another.
Adesanya then broke into some trademark moves as his beaten rival was attended to, before offering some more X-rated taunts for the camera in reference to Costa’s pre-fight jibes about his judo prowess.
“I wrap my d*ck around my waist, that’s a black belt motherf*cker!” Adesanya screamed from the octagon.
Fresh from his second title defense, Adesanya said he wanted a showdown with America’s Jared Cannonier next.
“I already DM’d Jared Cannonier. He’s a hell of a dude. I love his energy. He’s a beautiful man,” Adesanya said.
“I said you destroy Robert Whittaker and you’re next. He’s the one I want to fight next. He deserves it. If he beats Robert Whittaker handily and dominates him, he’s next.”
Meanwhile, the praise poured in from the fight world for the man nicknamed Izzy after he put on a masterclass on Yas Island.
Earlier in the night at the Flash Forum, Jan Blachowicz claimed the light heavyweight title vacated by Jon Jones as the Polish powerhouse knocked out Dominick Reyes in the second round of their co-main event contest.
After claiming the 205lbs strap, Blachowicz called on Jones to step out of retirement to face him.
“Jon Jones where are you?” shouted the Pole. “I’m here. This is how we do it in Poland. I’m waiting for you.”