LAS VEGAS -- Heavyweight world titleholder Deontay Wilder said over and over that his rematch with Luis "King Kong" Ortiz would end in a knockout. He promised one and advised all who would be watching not to go to the bathroom or to get a snack or to check their cell phone because it could come at any moment.

And it sure did.

Ortiz was soundly outboxing Wilder and was ahead on all three scorecards until Wilder crushed Ortiz with one devastating right hand to the forehead to knock him out in the seventh round and retain his title for the 10th time -- surpassing the number made by legends such as Mike Tyson and Joe Frazier -- before a crowd of about 10,000 on Saturday night at the MGM Grand Garden Arena.

"With Ortiz, you can see why no other heavyweight wants to fight him," Wilder said. "He's very crafty. He moves strategically, and his intellect is very high. I had to measure him in certain places. I had to go in and out, and finally, I found my measurement."

The smashing victory was the final hurdle to a rematch between Wilder and lineal champion Tyson Fury, who are penciled in for the main event of a joint pay-per-view between ESPN and Fox on Feb. 22 at the MGM Grand.

Wilder, who was boxing at the MGM Grand for the first time since he won his world title by one-sided decision against Bermane Stiverne in January 2015, took the fight with Ortiz even though he already had the rematch with Fury signed.

Given their tremendous power, Wilder and Ortiz began at a very cautious pace reminiscent of their first fight, but Ortiz did land a solid straight left hand. He also suffered a small cut on his scalp from an accidental head-butt.

Wilder (42-0-1, 41 KOs), 34, of Tuscaloosa, Alabama, barely threw or landed anything in the early going as he looked for a spot to launch his powerful right hand.

The slower pace favored the older Ortiz, but Wilder landed a solid right hand in the third round that knocked Ortiz briefly off balance in a round he otherwise got the better of.

Ortiz launched two hard left hands early in the fourth round that backed up Wilder, and when he landed another shot, Wilder responded by beating his chest.

Wilder seemed reluctant to throw his right hand much and took several one-two combinations from Ortiz during the middle rounds, including in the seventh round.

"I saw the shot, and I took it," Wilder said. "My intellect is very high in the ring, and no one gives me credit for me. I think I buzzed him with a left hook earlier in the round, and I took it from there."

Later in the seventh round, Wilder flicked out a jab and came behind with the heavy-duty right hand that hammered Ortiz flush and dropped him hard. He struggled to gather himself but could not as referee Kenny Bayless counted him out at 2 minutes, 51 seconds.

"This is boxing. I said that one of us was going to get knocked out and it wasn't going to go 12 rounds," Ortiz said through an interpreter. "I was clear headed when I hit the canvas. When I heard the referee say seven I was trying to get up, but I guess the count went a little quicker than I thought. I'm ready for any battle. I want to thank my team and everybody that came to see this fight."

Ortiz was leading 59-55, 59-55 and 58-56 at the time of the knockout.

The fight was a rematch of their memorable see-saw battle on March 3, 2018, in Brooklyn, New York, where they fought a contender for fight of the year in which Wilder dropped Ortiz in the fifth round, barely survived a massive onslaught of blows over the final 45 seconds of the seventh round and rallied to score a highlight-reel knockout in the 10th round of a fight Wilder led 85-84 on all three scorecards at the time of the knockout.

According to CompuBox statistics, Wilder, who was guaranteed $20 million, landed 34 of 184 punches (19%) but only one mattered. Ortiz landed 35 of 179 (20%), but could never get Wilder in the kind of trouble he had him in during the seventh round of the first fight.

Ortiz (31-2, 26 KOs), 40, a Cuban defector fighting out of Miami, was bidding to become the first Cuban to win a heavyweight title. He earned at least $7 million for the fight with Wilder.

"Ortiz is one of the best in the world," Wilder said. "You have to give him that. I want to thank his family for allowing Ortiz to come into the ring and share his energy with me. I hope one of the other top heavyweights gives this man another opportunity."

Ortiz had come in top condition and was lighter and trimmer than he was the first time, but still succumbed to Wilder's destructive power, which propelled him into the sequel with Fury.

When Wilder and Fury met last December in Los Angeles they turned in a memorable fight in which Fury outboxed Wilder for long stretches, but Wilder scored two knockdowns, one in the ninth round and a huge one in the 12th round that Fury somehow survived. The fight was ruled a split draw with Wilder winning 115-111, Fury winning 114-112 and the third judge scoring it 113-113.

When they finally agreed to terms for a rematch -- there is also a third fight that is part of the deal -- each man was to have two interim fights. Fury (29-0-1, 20 KOs), 31, of England, got through his, a second-round wipeout of Tom Schwarz on June 15 and a decision in an unexpectedly grueling fight with Otto Wallin in which Fury suffered a horrendous cut over his eye, on Sept. 14. Wilder smoked mandatory challenger Dominic Breazeale in the first round on May 18 and then struggled with Ortiz before turning out the lights.

"Next, we have Tyson Fury in the rematch. It's scheduled for February, so we'll see," Wilder said. "Then, I want unification. I want one champion, one face and one heavyweight champion - Deontay Wilder. The heavyweight division is too small. There should be one champion and it's Deontay Wilder."