LAS VEGAS — There’s an easy well to tell how a fighter has made it: When other fighters begin talking about him, it’s a sure sign.

Khamzat Chimaev clearly has made it. We knew that when Nate Diaz agreed to fight him in the main event of UFC 279 on Saturday at T-Mobile Arena in what is likely Diaz’s last fight in the UFC.

Diaz is shrewd in his own way and he wasn’t going to go out fighting a guy no one ever heard of and didn’t care much about.

At Wednesday’s media day, Kevin Holland had plenty to say about Chimaev, who has only five fights in the UFC. Holland, who himself is a rising star and will fight Daniel Rodriguez on Saturday’s main card, essentially said Chimaev’s tough guy act is phony.

“I feel like he likes the f***ing media,” Holland said when asked about Chimaev. “I feel like he only does this extra wannabe street s*** when the media is around. Other than that, he doesn’t do it. When you guys [in the media] aren’t around, he wants to do fist bumps and he wants to be your best friend.

“When you guys are around, then all of a sudden he’s like, ‘Roar! I’ll rip your f***ing head off.’ You ain’t ripping s*** off, dog. Let’s be real. You want a paycheck just like the rest of these guys around here.”

Chimaev and middleweight Paulo Costa had an altercation at the UFC Performance Institute earlier in the week. Costa said he was willing to fight Chimaev on the spot. Costa said that when Chimaev said he’d fight him, Costa walked toward the cage Chimaev was in. Members of Chimaev’s team blocked Costa from entering, leading Costa to refer to Chimaev as “a fake gangster.”

And there are more, but you get the idea.

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Chimaev, though, does seem different this week. In many ways, his quick rise to popularity is because he’s been seen as something of a Russian version of Diaz. He came into the UFC virtually unknown and quickly showed that he’s violent, he’s unapologetic and that he’d put anyone in his targets.

When he debuted in the U.S. at a UFC Fight Night show at Apex against Gerald Meerschaert, he took over the pre-fight news conference, taking jabs at everyone on the card.

He was so confident of victory over Diaz that when the fight was announced in July, he told ESPN, “I am going to handle Nate Diaz’s funeral with the UFC.”

On Wednesday, he spoke barely above a whisper during a brief media day appearance and then again in a sit-down interview with Yahoo Sports. Maybe that shouldn’t come as much of a surprise, given that this is his first main event and he’s headlining a pay-per-view against one of the most iconic athletes in UFC history. It’s his name, as the higher-rated fighter, first on the promotional materials — the fight officially is billed as Chimaev-Diaz, not Diaz-Chimaev — and he’ll make the ring walk last.

As the pay-per-view headliner, the demands on him are far greater than anything he’s ever had before, and he still has to cut to at least 171 pounds. So there’s a lot on his plate and perhaps his lack of boasting and outlandish behavior that characterized so many of his other UFC bouts is a direct result of that. But his temperament was so different from the past, it was the first question I asked him when I sat with him. He insisted nothing’s different.

“It’s the same thing,” he said. “It’s the same thing I did all my life. I like when I do the same things. I like to eat the same breakfast every day. It’s no different.”

He said the joy that was so plainly evident in his earlier UFC fights remains, even if it isn’t so obvious.

Chimaev on Diaz: 'I have to go and take his head off'

Chimaev is a -1200 favorite at BetMGM, making him one of the biggest favorites in a main event in UFC history.

When the fight was made, Diaz’s manager, Zach Rosenfield, went out of his way to make the point that the fight wasn’t offered and that instead, Diaz asked for it. But Diaz is now saying he took the fight only as a way to complete his obligations to the UFC.

His comments about Chimaev in that are telling, however.

“I’ve been stuck in the cage for a long time and I’ve got to do what I’ve got to do to get the f*** out,” Diaz said when asked his thoughts on Chimaev. “Whether it’s fighting the toughest guy or the newest guy or whatever you want to make of him or call him, I’m just ready to rock and roll.”

So if you peel back the layers of the onion a bit, is he saying that Chimaev is the toughest guy? Perhaps.

Chimaev, though, showed a little respect in return, something he’s rarely done. It may mean nothing or just be indicative of the fact that he’s bored to tears talking and is just eager to fight, but offering even faint praise to an opponent is new for him.

“All moments in the UFC are big moments for me, you know?” Chimaev said. “It feels amazing. I’m fighting Nate Diaz, one of the guys whose been 15 years in this game, one of the legends. Maybe it’s his last fight, who knows, but I’m happy.”

But he wouldn’t be Khamzat Chimaev if he offered just platitudes. Even though he was speaking softly, he gave a glimpse of his mindset.

“I have to go and take his head off,” Chimaev said. “I came here and don’t take the points. I came here to smash somebody and take his head.”