LAS VEGAS >> Conor McGregor backed up every single word.

The Irish mixed martial arts sensation won the UFC interim featherweight title at UFC 189 on Saturday night, stopping Chad Mendes with three seconds left in the third round with a vicious series of strikes.

McGregor (18-2) spent much of the first two rounds on his back, but he finished the fight with a lightning-quick combination soon after he reached his feet. After a big left hand put Mendes down, McGregor pounded away for the stoppage and then jumped onto the cage in celebration.

McGregor later sunk to his knees in tears while thousands of Irish fans at the MGM Grand Garden Arena roared in adoration of a loquacious fighter who can make good on every boast and threat.

“To come in here and hear all this applause, it’s just amazing,” McGregor said. “I truly appreciate it.”

Mendes (17-3) stepped in for injured featherweight champion Jose Aldo just 2 1⁄2 weeks ago, and the elite wrestler was in control of the fight until McGregor’s heavy hands changed everything in an instant. Mendes embraced McGregor in sportsmanship after a promotion dominated by high-level trash talk, most of it from the pugnacious Irish brawler who already looks comfortable with a title belt around his waist.

“I’ve been hearing all the while that I’ve been protected from this kind of opponent, that I’ve been gifted a title shot,” McGregor said. “So when my title shot went running and they gave me the challenge I was supposed to be protected from, I (decided) that I’m just going to prove to people that I’m a true fighter. It doesn’t matter who it is, I’ll show up and I’ll put a finish on any fighter.”

There was one fighter from Hawaii on the card — Louis Smolka of Kapolei defeated Neil Seery via unanimous decision.

“We game-planned perfectly for him,” Smolka said. “I was stoked I got to show off my grappling, this is the first time I’ve been able to do so in the UFC, but if you watch my fights prior to coming to the UFC you’ll see that I’m a very well-versed grappler. I wanted to go in and change levels so I could land the takedown.

“BJ Penn is my hero, and I wish that I could have fought on the same card as him just once, but I’m honored to have fought on this card as he got inducted into the Hall of Fame earlier today. I’m of the generation of Hawaiians that grew up idolizing him, he’s one of us, he’s one of our own and to see him get honored this way makes you feel like it’s a possibility for you one day too.”

Also on the undercard, Robbie Lawler defended his welterweight title in spectacularly bloody fashion, stopping Canada’s Rory MacDonald with a big left hand early in the fifth round. Jeremy Stephens stopped Dennis Bermudez 32 seconds into the third round of a wild brawl featuring multiple knockdowns by both fighters, highlighting an action-filled pay-per-view card.

But everything was a prologue to the biggest moment yet in the meteoric MMA rise of McGregor, the former plumber from Dublin who has rocketed through his sport by deploying his sharp tongue as much as his heavy hands.

McGregor has won 14 consecutive fights, and now he has a UFC belt and an enormous future date with Aldo.