To find clues about the soured relationship between Francis Ngannou, the heavyweight champion in the Ultimate Fighting Championship, and Dana White, the organization’s president, note White’s hard-to-ignore absences on Saturday night in Anaheim, Calif.

Moments after Ngannou’s unanimous-decision win over the previously undefeated challenger, Ciryl Gane, White was not in the octagon to strap the championship belt around the winner’s waist. One fight earlier, he draped one over the shoulder of Deiveson Figueiredo, who had defeated Brandon Moreno for the flyweight championship.

White also did not attend the postfight news conference, where he normally rattles off attendance and gate revenue numbers and rehashes the night’s action with reporters.

Another signal that Ngannou, a power-punching 35-year-old native of Cameroon, is seeking a way to win bigger paydays from the U.F.C. came minutes after the fight, when he spoke openly of starting a professional boxing career.

“Boxing is always in the back of my pocket,” said Ngannou, whose record improved to 17-3. “It’s something I must do before the end of my career.”

Ngannou, who began his career in Paris, and Gane, who was born and raised there, once trained together, providing a built-in story line before the fight on Saturday night. Another subplot involved Ngannou’s contract status.

The Gane bout was the final one in an eight-fight deal Ngannou signed in 2017, but standard U.F.C. contracts give the organization rights to a title fight winner’s next bout. In theory, the clause could have bound Ngannou to the U.F.C. indefinitely. If Ngannou had kept winning, he couldn’t use other suitors to nudge the U.F.C. into boosting his payouts, but if he had lost on Saturday he would have hit free agency with diminished bargaining power in a sport where fighter pay is a continuing, contentious issue. At the news conference, Ngannou clarified that if he does not fight again before the end of 2022, he will become a free agent.

According to figures released by the California State Athletic Commission, Ngannou was guaranteed $600,000 for fighting Gane, who earned $500,000, figures that are dwarfed by the purses elite boxers earn. In December, Gervonta Davis, whose nickname is Tank, earned a $1 million guarantee for his title defense against Isaac Cruz in Los Angeles. And in November, the welterweights Terence Crawford and Shawn Porter split a $10 million purse for their title fight in Las Vegas.

In contrast, the combined guarantees for every fighter on the U.F.C. 270 card on Saturday totaled $1.84 million.

So if Ngannou actually appears in a boxing ring — and he has sparred verbally on Twitter with the heavyweight champion Tyson Fury — he might be chasing a pay raise. Or he might want more flexibility.

“It’s not simply money,” he said. “It’s also the terms of the contract.”

And if he continues with the U.F.C., he will have options. Gane, one of just two fighters to force Ngannou to fight the five-round distance, lobbied for a rematch after losing. Jon Jones, a former light-heavyweight champion, also teased the possibility he would challenge Ngannou.

“If this is the apex of heavyweight fighting, I’m excited,” Jones tweeted. “Got some more records to break.”

Jones, as he made clear on Twitter, watched the bout at home. Visible on the pay-per-view broadcast was Mike Tyson, the Hall of Fame boxer credited with coining the phrase “Baddest Man on the Planet” to describe boxing’s heavyweight champion. The U.F.C. appropriated the nickname for its own heavyweight champion as it trumpeted a showdown between Ngannou’s raw power and Gane’s refined technique.

Before Saturday night, Ngannou had never won by decision in the U.F.C.

Early on, the pair fought at the pace and distance dictated by Gane, a converted kickboxer. Late in the second round, Ngannou, who is 6 feet 4 inches and 257 pounds, inched into striking distance, but he missed his biggest punches while Gane clipped him with a right hook and popped him with a right jab.

In the third, Ngannou shifted tactics. He foiled an attempted kick from Gane, lifted him off the ground, then slammed him to the canvas like a pro wrestler. From there, he spent much of the rest of the fight neutralizing Gane’s kickboxing with viselike body locks and punishing takedowns.

“It was not a surprise,” Gane, now 10-1, said of the change in tactics. “He did it, and he did it very well.”

Ngannou said he tore a knee ligament while training for the Gane fight, and the injury led him to practice grappling because it required less mobility than a stand-up striking match would.

Later, he strode into the news conference wearing a dark-green suit, white shirt and gold tie, and placed his title belt on the table. A reporter asked whether White’s decision not to present him with the belt personally inside the octagon was related to jockeying over his contract.

“I don’t know,” Ngannou said. “You’ll have to ask him.”