Deontay Wilder unleashed the crushing right hand that’s long been considered the best in the business and was back in the win column in less than one round.

He believes that same power could quickly put him back on top of the heavyweight division.

“When you fight Deontay Wilder, you have to have your A-plus-plus game,” Wilder said.

Or an A-plus chin.

Wilder knocked out Robert Helenius in the first round Saturday night, powerfully punching his way back to victory after consecutive losses to Tyson Fury.

The former heavyweight champion moved cautiously for most of the round before launching the shot that he knew ended it. Wilder, wearing trunks that looked like sparkly bottoms of a gladiator outfit, was posing against the ropes even before the fight had been stopped.

Wilder (43-2-1, 42 KOs) won emphatically in his first fight since getting stopped twice by Fury, the latter in the 11th round last October after Fury got up from two knockdowns.

But Helenius (31-4) wasn’t getting up from the straight right hand that ended the match with three seconds remaining in the first round at Barclays Center in Brooklyn.

Fury was able to deal with Wilder’s power — and he’s been the only one so far who has — getting up from four total knockdowns in their three fights. But Helenius wasn’t in that class.

He used his roughly 40-pound edge to move Wilder back for much of the round, and had him back in the corner when Wilder unleashed the right that ended the Finnish fighter’s hopes of moving closer to a title shot.

“I set him up,” Wilder said. “I allowed him to reach and when he reached, I attacked. It was a great fight.”

Wilder could quickly get another one for the heavyweight title after showing again why his power makes him one of the can’t-miss attractions in the sport.

He held a portion of the heavyweight title for five years and could seek a chance against Oleksandr Usyk, who owns the three belts other than the one Fury took from Wilder. Other names that will be mentioned include former champions Anthony Joshua and Andy Ruiz Jr.

“I’ve been hearing rumors about Usyk, but he’s not here, is he?” Wilder said. “When guys see these knockouts, they turn the corner away from me.”

Wilder came in at just 214 1/2 pounds, losing most of the weight he added for the final two fights against Fury and returning to a weight that is comfortable to him but light for most heavyweights.

It made no difference in his fist. He improved to 5-0 in Brooklyn with five KOs — the last two coming in the first round. The previous one, against Dominic Brezeale in March 2019, was his first return to the ring after a draw against Fury in their first fight.

Wilder then went on to stop Luis Ortiz that November but hadn’t won since. He turns 37 next week and said he only wants to fight three more years, but is willing to do whatever it takes during that time to get back on top of the division.

“Deontay is back and the excitement in the heavyweight division is back,” he said.

Wilder finally got to work after Caleb Plant (22-1, 13 KOs) knocked out Anthony Dirrell (34-3-2) in the ninth round of their super middleweight matchup between past champions. Plant lost his belt in his previous fight when he was stopped by undisputed champion Canelo Alvarez.

The fight featured plenty of holding and wrestling and occasional lengthy stretches with little punching, bringing down boos in Brooklyn. Suddenly, Plant followed up a left to the body with a left hook to the head that dropped Dirrell to the canvas and left him there for a few minutes, with Plant standing above him and mimicking a shoveling motion as if digging the veteran’s grave.

“I was in control the whole time,” Plant said. “My coach told me to stay patient and ease in and that’s what we did. Then, boom!”

In the opening fight of the pay-per-view, Emmanuel Rodriguez handed Gary Antonio Russell his first loss with a unanimous decision in a bantamweight bout that was stopped seconds into the 10th round after Rodriguez (21-2) was hurt by a clash of heads in the ninth. The former champion from Puerto Rico had dominated the fight and knocked Russell (19-1) down late in the eighth round.

Their first fight in August 2021 was also cut short because of a head butt, that one coming in the first round and causing the bout to be a no-contest.