But an incident in the second half threatened to overshadow the spectacle, with claims from the Broncos that Roosters recruit Spencer Leniu levelled a racial remark at Indigenous five-eighth Ezra Mam during a scuffle.
Referee Adam Gee placed the incident on report at Allegiant Stadium, with the match review committee to probe it in the days that follow.
If Saturday evening's first game (Sunday AEDT) educated the USA on razzle-dazzle rugby league, the second was all about the uncompromising physicality of the 13-man game.
Victor Radley and Lindsay Collins were chief enforcers as the Roosters ground the Broncos into the turf, helping their side claim a major scalp in their first start this season.
The Broncos and Roosters turned on the physicality as the NRL hit Vegas. (HANDOUT/NRL PHOTOS)
Under the bright lights of Sin City, the Broncos were unable to atone for their own sins from the 2023 grand final, bullied onto the back foot after conceding early.
Reece Walsh gave the Broncos hope either side of the break.
First, he slipped past Joseph-Aukuso Suaalii and kicked through the line for a flying Deine Mariner, who made it 8-4 at halftime.
Then Walsh had a try of his own in the early minutes of the second half, after the ball travelled through hands on the left side.
But the Broncos, for all their firepower up forward, could not match the Roosters' aggression and appeared to be missing Dolphins recruit Tom Flegler as they fought to stay in the game.
As the sides showed America all that rugby league had to offer, Roosters centre Joey Manu reminded Australia just how much he'll be missed when he moves to rugby union in 2025.
Reece Walsh was among Brisbane's brightest lights in their disappointing start to the season. (AP PHOTO)
The New Zealand international picked off a Mam pass in the opening five minutes, cruising 30 metres to score and help his side take early advantage.
But Manu saved his best trick for after the break, firing a no-look flick pass around the corner to send Junior Pauga over for a spectacular try down the right.
It was reminiscent of Joey Leilua's famous flick pass to Jordan Rapana at Leichhardt Oval in 2016, but the only thing the American audience could've compared it to would've been a magic trick from a Las Vegas show.
Walsh fought hard, and Adam Reynolds looked more comfortable playing within the confines of the smaller field as the game went on.
But a late try to Radley proved fitting reward for the lock's leadership in the forward pack and had the Roosters home for an upset.
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