LAS VEGAS — Ever been to a good Vegas show? The singing, the dancing and theatricality. The smoke, the lights and the smells.

We saw one on Sunday night, not in some dark casino ballroom or dark hotel lobby, but in a football palace built just off Las Vegas Boulevard. There was a lot of smoke (the pregame fireworks left a haze hanging for three quarters). There were main characters and leading players (Heisman Trophy replacements, quarterbacks Miller Moss and Garrett Nussmeier). There was even dancing (an LSU player was penalized for a hip-thrust jig in the second quarter).

Singing, chanting, waving? There you had it, a few exuberant fan bases, two of the biggest brands in college football colliding in front of them.

It all came down to a sensational final act: a drive in the final minutes of the game, a heroic catch and a heart-stopping run for a winning touchdown.

USC and LSU delivered a playoff-worthy performance with a championship feel in front of millions of spectators, all on a Sunday night before the long holiday — an electrifying, heart-pounding Las Vegas act that Wayne Newton himself would be proud to recommend.

The score — USC 27, LSU 20 — doesn’t do justice to the beauty of it all, the intense moments, the great quarterback play, the momentary defensive lapses and the waves of side-splitting momentum changes.

And now we have to dissect the show and review—or overreact to—a Week 1 matchup between two teams that, let’s face it, we don’t really know much about.

Can USC now seriously competing in his new, big, bad competition?

Can LSU recover and reach a 12-team playoff game?

What we saw on Sunday night was a Trojans defense, revamped and strengthened by a new coordinator, that tackled better than any Lincoln Riley defense in his eight-year head coaching career (the unit held LSU back on two crucial fourth-quarter drives). We saw a quarterback, Moss, who shined on the biggest stage after waiting three years for his shot (he completed 75 percent of his passes and finished with 378 receiving yards).

We saw receiver Kyron Hudson make two of the best catches you’ll ever see: an acrobatic one-handed catch in the third quarter and a game-winning catch in the fourth quarter when he managed to snag a pass from Moss on USC’s final touchdown march despite being hit (and a goaltender hit at that) by an LSU defender.

We saw, perhaps most surprisingly of all, a USC defensive tackle, yes, tackle. The Trojans stopped the run (minus a 39-yard burst, LSU had just 78 yards rushing) and put together a first-quarter goal stand (LSU failed on a fourth-and-goal from the 3).

Those superlatives made their coach the happiest. Riley seemed almost surprised, certainly impressed, with a team that ranked 119th in the country a year ago.

Did we do that? How? Are you sure?

Riley made one of the most talked-about moves of the offseason, firing coordinator Alex Grinch and hiring UCLA’s D’Anton Lynn, one of the most heralded young defensive minds in the game. New coach. New scheme. New players. New mentality.

“I was proud of how hard and how well we played and how much we trusted it and didn’t panic. We kept fighting,” Riley said. There’s a “vibe” to the defense, he said — a confidence. “It was so cool to see that moment and be in that arena, how much we trusted it (the new system).”

The overreactions are clear:

• Moss, sharp and clear, collected and calm, is Riley’s latest contender for the Heisman Trophy.

• USC’s defense is physical, aggressive and smart and is back in championship form.

• Riley, the $10 million player in his third season, will finally bring Los Angeles a championship.

On the other hand, the other $10 million man, Brian Kelly, was “angry,” he told reporters afterward, especially with an offense that failed to turn a one-score game into two in the second half. The Tigers had that chance twice, leading 17-13 with possession and momentum on their side.

They lost a yard on a third-and-1, stopped by Lynn’s new defense. On another drive, they gained 3 yards when they needed 6, again stopped by Lynn’s quick-tackling defenders who didn’t make it to the first-down line.

They wasted a 304-yard outing by new starter Nussmeier with longtime starter, Heisman winner Jayden Daniels, watching from the sidelines. In the stands, those raucous Louisianans streamed toward the exits, into the dry Vegas heat and, at one point, headed for a cross-country flight home, irritated and (probably) hungover.

These are the games that make you and break you. They get coaches fired and hired, they energize, inspire and rob fans.

“That was a playoff game,” said USC athletic director Jen Cohen.

It certainly felt like it: two giants from the two most powerful football leagues, each with their own commissioners watching from this football palace, and the bright lights of the Strip streaming in to create a magical Vegas spectacle.

One with a new twist.

“Pretty good Big Ten football game today,” Riley smiled.