LAS VEGAS – Daniel Cormier isn’t worried about the critics who called his in-cage confrontation with Brock Lesnar “fake, staged, WWE” or anything of the sort.

Following Cormier’s title-winning knockout of Stipe Miocic (18-3 MMA, 12-3 UFC) in Saturday’s UFC 226 headliner, Lesnar (5-3 MMA, 4-3 UFC) entered the octagon and sparked chaos with Cormier (21-1 MMA, 10-1 UFC). There was shoving and harsh words exchanged, and that moment will certainly be a centerpiece of the promotional material for their heavyweight title bout, which is expected to happen next year.

Lesnar’s appearance at UFC 226, which took place at T-Mobile Arena in Las Vegas and aired on pay-per-view following prelims on FS1 and UFC Fight Pass, came as a surprise to most. Cormier said he didn’t know the ex-champ would be there until he saw him just minutes before walking to the octagon.

“It was weird,” Cormier said. “I run sprints before every fight. We go out, we find a little hallway, and I just bust out as many sprints as I can to get my heart rate up. As I was walking back to the arena I see Brock Lesnar walking behind me, so I’m like, ‘Oh, what’s Brock Lesnar doing here?’ Then when I’m in the octagon waiting for Stipe, he was standing there, like smirking at me. So I was like, ‘Oh, I guess Brock Lesnar’s here to pick a fight.’ So I called him out. I’ve known him for a long time. I told him I wanted to kick his butt, and I will kick his butt when we fight.”

The interaction between Cormier and Lesnar was met with mixed reaction. One side felt that type of conduct has no place in the octagon or the sport of MMA. The other, however, enjoyed the chaos that will get even further energized before a bout between the two takes place.

Cormier, 39, is aware of the critical side, and he fired back at those who feel that way.

“‘Staged, they’re idiots.’ Fine. Stay broke,” Cormier said. “You got a guy like Brock Lesnar in front of you, and you don’t go crazy on him? Are you crazy? When Brock decided to step in the octagon with me – he’s a pro wrestler. He does fake fighting. So I’ll do fake fighting with you until I put my fist up inside of your face. I’ll do fake fighting with you, Brock, then I’ll punch you upside your head. So, yeah, you guys call it fake online. I see a bunch of fighters, ‘Oh that’s so fake. I don’t want to watch this.’ Tune in and keep lacing my pockets. You guys got to get on board. These guys get on the microphone after their fights and say, ‘Yeah, it’s whatever the UFC decides.’ OK.”

Before the fight between Cormier and Lesnar takes place, Lesnar must first complete his six-month drug testing window with the U.S. Anti-Doping Agency (USADA). Lesnar is still under suspension for a pair of failed tests stemming from his UFC 200 fight with Mark Hunt, which he won before the result was overturned to a no-contest.

Throughout his career Cormier has been outspoken against those who have failed tests for performance-enhancing drugs, namely with former opponents Jon Jones and Anderson Silva. He said his thoughts on PED users hasn’t changed, and he intends to go to whatever lengths necessary to ensure there’s no chance of foul play when he eventually does step in the octagon with Lesnar.

“Brock’s got to be clean,” Cormier said. “I’m not going to fight him if he’s not clean. We’ll do USADA testing, and we’ll do other testing. We’ll do testing above USADA to make sure this man’s clean, because I’m not going to fight him if he’s cheating. I’ve done that on a number of occasions already (with others). I don’t want to fight him if he’s dirty, man. Do it the right way.”

A fight between Cormier and Lesnar comes with some history attached. Cormier said their relationship goes back more than 20 years to their amateur wrestling days. The reigning heavyweight and light heavyweight champ said interactions have been more than friendly, but now that they’re on each other’s radar for a fight, that’ll change.

“I’ve known Brock since 1997,” Cormier said. “When he pushed me like that it was very odd. I was like, ‘Yo!’ I saw Marty Morgan out there. Last time I saw Marty I was like, ‘Woah, I haven’t seen Marty!’ Last time I saw Marty, Brock was getting his face bashed in by Cain Velasquez. I was like, ‘Marty, you guys are back.’ They’re back in the game. Brock and I wrestled in a 1998 junior college finals together. He was the heavyweight champ, then when he was at Minnesota I was at Oklahoma State, so we wrestled each other twice in duel meets. Not against each other, but the teams wrestled each other.

“Then when Brock was wrestling in WWE, he was always good to me and my family. We would go to the matches. He would take care of my kids. When you step in the octagon your emotions are raised a little bit. Brock pushed me, then (my coach) Rosendo pushed him. It was crazy, because Rosendo is like 5-foot-nothing. That’s what my team does for me.”

For complete coverage of UFC 226, check out the UFC Events section of the site.