Doctor breaks down why Ilia Topuria's punch knocked out Alexander Volkanovski but Paulo Costa's head kick did not drop Robert Whittaker

UFC 298 featured two thrilling fights in the co-main and main events, with a featherweight championship bout between Alexander Volkanovski and Ilia Topuria and a middleweight clash between Robert Whittaker and Paulo Costa taking place.

Although Whittaker won via unanimous decision, Costa landed an excellent head kick toward the end of the first round that seemed to rock his opponent but did not materialize in a finish.

Dr. Brian Sutterer explained on his YouTube channel why the head kick did not get its desired outcome for Costa:

“Now, like many people, I was stunned that this kick from Costa did not knock out Whittaker... Whenever two bodies collide, there’s conservation of momentum... It’s dependent on if you’re going towards or away from the object... With Whittaker, as this kick comes in, he’s moving backwards and so Costa’s leg is coming in this way but Whittaker is moving in the opposite direction... So yes, it still is a very violent, vicious hit, but the fact that Whittaker is moving backwards, there’s not going to be as much potential energy that can be transferred into the brain resulting in the concussion.”

Sutterer then compared Costa's strike to Topuria's knockout of Volkanovski with a clinical right hook and how the momentum favored 'El Matador':

“If we compare that thought to what happened with Volkanovski, we’re going to see the exact opposite here. I’m not sure if it was because Volkanovski was trying to move away from another potential little left hook but what do we see but Volkanovski’s head go into directly where Topuria’s fist is coming... Now Volkanovski’s head, he has momentum going in this direction, velocity coming inward combined with the momentum of Topuria’s fist coming from this side and so that’s going to result in a move violent transfer of energy.”

Check out Brian Sutterer's full comments on Ilia Topuria and Paulo Costa's strikes (4:42):

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Conor McGregor responds to Ilia Topuria's post-fight callout

Ilia Topuria used his post-fight octagon interview to call out UFC superstar Conor McGregor.

After being crowned the featherweight champion, Topuria spoke to Joe Rogan and called for the UFC to organize its first event in Spain, while simultaneously challenging McGregor to fight him in his home country.

McGregor took to an Instagram post of Topuria's quote and responded with a non-committal remark about his impending return and a potential matchup:

"I have huge balls, I've 4 kids."