Deontay Wilder produced a devastating knockout to beat Luis Ortiz just when his WBC heavyweight belt looked to be slipping away.
The 'Bronze Bomber' was being outboxed and outclassed by his 40-year-old opponent before unleashing a vicious blow in the seventh round that ended the contest.
It was just what Wilder needed while trailing by a long way on the scorecards at MGM Grand Garden Arena and on his way to a points defeat.
It looked for a lot of the evening like there could have been another huge upset in the heavyweight division this year after Andy Ruiz Jr's win over Anthony Joshua.
Wilder didn't land a single blow on Ortiz all fight, but came up trumps with a huge right hand when it mattered.
Ortiz was laid flat on the canvas and failed to make the 10 count as Wilder held onto his WBC belt in the most spectacular style.
Ortiz nearly shocked Wilder in their first bout in Brooklyn in 2018.
The Cuban rocked his opponent in the seventh round in that bout before Wilder battled back to win in the 10th round.
And it was in the seventh round on this occasion when the drama unfolded once again.
This time it was Ortiz who was rocked in the seventh round, and there was no recovering from this huge blow.
Wilder told Sky Sports: "These guys have to be perfect against me for 12 rounds. I just need to be perfect for two seconds and I proved that.
"I saw he was tiring, got my range and then bam - good night."
He told US broadcasters FOX Sports: "Next up is Tyson Fury and it is scheduled for February. Then after that I want a unification bout. We need one name, one champion, one face. It's too confusing for the fans."