LAS VEGAS – The main event on Saturday at the MGM Grand was the rematch between Leo Santa Cruz and Carl Frampton, two pretty damned good fighters. The star of the show – and the best fighter in the building – fought in the co-feature, though.

Mikey Garcia’s future seemed murky only six months ago, when he was in the midst of a 2½-year layoff because of a promotional dispute.

That’s a long time away. Fighters generally can’t return from such a hiatus and regain the form they once had, as we saw when a less-than-peak Andre Ward struggled to outpoint Sergey Kovalev in November.

Garcia is different, as we saw Saturday.

Mikey – a genteel name that belies his savagery – tore then-unbeaten and WBC lightweight titleholder Dejan Zlaticanin apart in only 8 minutes, 21 seconds of boxing.

Photo by Esther Lin/Showtime

From the outset, the master of distance kept the Montenegrin at the end of his left jab and followed with power rights. Zlaticanin had never faced anything as baffling – or dangerous – as this. He had no clue how to cope.

And the moment Garcia saw his opening, the end came quickly and brutally. Right uppercut, grazing left, crazy straight right. The loser went down in a heap and didn’t move for several minutes, frightening evidence of Garcia’s destructive power.

Garcia, thus, won a major title in a third weight division. More important, he has demonstrated that the time away meant nothing: Garcia is back and might be better than ever.

And he did it in only two fights: He prepared for his world title challenge by stopping former featherweight champ Elio Rojas in July. That’s it: one fight and then one of the more memorable knockouts you’ll ever see.

So much for rust.

Of course, we should restrain ourselves to a degree when it comes to the hyperbole. Zlaticanin was an unbeaten (22-0 coming into the fight) titleholder and was supposed to be a big puncher, which is why some experts gave him a chance against Garcia, but he hadn’t proved himself against the best in the business.

Garcia will have to beat a better opponent to climb onto pound-for-pound lists. And I have no doubt he will, whether that’s RING 135-pound champion Jorge Linares or the best at 140.

I hesitate to say this given my respect for Vasyl Lomachenko but I also think Garcia might have the all-around game to give the immensely gifted Ukrainian all he could handle, should the two meet in what would be a fascinating fight.

Photo by Esther Lin/Showtime

The younger brother of trainer Robert Garcia, who works his corner, is 29 and in his prime. The time away means his body was spared more than two years of pounding.

He also seems to be hungrier than he was early in his career, as if he learned to appreciate what he has during the time off. He’s more mature. And he obviously was never forgotten by his fans, who bought into him a long time ago.

“I was always in shape and I was always active,” he said of his hiatus. “I think the layoff allowed me to reignite my fire and my passion and bring back that love for the sport. And in that 2½-year layoff I always had the support of my loyal fans. I really appreciate the love and support of all the fans.”

He definitely has that. The 10,085 inside the MGM Grand Garden Arena were there primarily to see Santa Cruz vs. Frampton but they saved plenty of enthusiasm for Garcia, repeatedly chanting “MIKEY! MIKEY! MIKEY!” as he destroyed Zlaticanin and then erupting when he finished the job.

I’m willing to bet that it was his knockout – not Santa Cruz’s victory – that fans were talking about afterward. Garcia stole the show.

And who won’t want to see him in his next fight? His performance on Saturday night is the kind that makes it impossible to look away.

The best is yet to come.

Photo gallery: Frampton-Santa Cruz II, Garcia-Zlaticanin