LAS VEGAS -- There would be no staged skits or trading of venomous insults on this day as both Floyd Mayweather and Conor McGregor arrived more than 45 minutes late to the final news conference on Wednesday, just three days out from their blockbuster pay-per-view fight. 

Unlike the wild four-city international media tour in July that announced Saturday's fight at T-Mobile Arena (Showtime PPV, 9 p.m. ET) that was reviled for its crass overtones, this was a largely ho-hum (keyword: boring) affair. 

No spectators were allowed access inside the MGM Grand's KA Theater and even the media turnout was no better than sparse. This was a boxing news conference presented under archaic boxing rules, unlike the UFC versions, which often resemble a party. 

With the fight just about completely sold from the standpoint of hype, Mayweather left his salesman personality behind to deliver a subdued yet serious message to McGregor, the UFC's lightweight champion, whom he broke script long enough to call "a stand-up guy" and "hell of a fighter." 

Mayweather, 40, who returns from a two-year retirement, counted down all the game plans prior opponents have come in with -- everything from going to the body to putting too much emphasis on Mayweather's brittle hands. 

"After 21 years, I've been hit with everything, and I'm still right here," Mayweather said. "One thing that you must know about the sport of boxing and about combat sports, remember -- if you give it, you must be able to take it.

"Listen, last time I checked, nobody is walking me down. It's called smarts. It's called having an IQ. It's called having patience. And from Day 1, everything that my dad taught me, I still know today. Every combination that was taught to me, I know. And any and everything about boxing that can be done, I've done it -- not just once, not just twice, a thousand times. 

"I was born a fighter. I will die a fighter."

Likely tired of talking about the fight throughout a condensed two-month build, both fighters were brief. 

The only fireworks of any kind came from Mayweather assistant trainer Nate Jones, who heckled McGregor from the crowd and was publicly scolded by Mayweather for being unprofessional. McGregor, for his part, quietly countered by calling Jones a "b----" and telling him to do what he's told.

After a two-sentence introduction from an equally subdued UFC president Dana White, the 29-year-old McGregor made sure to mention the mistake he believes Mayweather made in successfully petitioning the change from 10-ounce to 8-ounce gloves.

"We are prepared for 12, three-minute rounds of non-stop pace and I will go forward and put the pressure on him and break this old man," McGregor said. "Eight-ounce gloves -- he made a big, big error, in my opinion. I don't see him lasting two rounds. I think I'll have the decision to end it in one.

"I'm going to f--- this boy up ... You should have left me where I was. This man is not on my level. He's not even a quarter of the man I am."

Mayweather's serious tone oozed confidence and closed by reminding McGregor one last time that he's going to need to answer inside the ring for all of the talk leading up to the fight.

"He's going to bring his best, and it's not going to be easy, Conor. It's not going to be easy," Mayweather said. "Remember, [Manny] Pacquiao got bombs. Canelo [Alvarez] got bombs. Shane Mosley had bombs. And all those guys are going into the Hall of Fame.

"The same way you give it, you have to be able to take it. Remember this."