LAS VEGAS — Manny Pacquiao knocked down Keith Thurman in the first round and persevered for an exciting split-decision victory Saturday night, adding a third straight win to his career resurgence after turning 40 years old.

Pacquiao (62-7-2) dropped his previously unbeaten opponent with a combination late in the first round, and the Pac-Man dominated the opening rounds with a combination of flair and power that recalled the incredible prime of the only eight-division champion in boxing history.

Thurman (29-1) showed remarkable tenacity in rallying through the middle rounds, repeatedly testing Pacquiao’s chin with big shots. Neither fighter managed another knockdown, but they pushed relentlessly in front of a sellout crowd at the MGM Grand Garden that repeatedly chanted the Filipino senator’s name from the moment he reached the ring.

“It was fun,” Pacquiao said. “My opponent is a good fighter and boxer. He was strong. … I think he did his best, and I did my best. I think we made the fans happy tonight because it was a good fight.”

Two judges scored the bout 115-112 for Pacquiao, while Glenn Feldman scored it 114-113 for Thurman. The Associated Press also scored it 115-112 for Pacquiao.

Pacquiao appeared to be declining as recently as two years ago, when he lost a listless decision to Jeff Horn. But while his political career flourished, Pacquiao returned to the ring a year ago and put together solid back-to-back victories over Lucas Matthysse and Adrien Broner.

Thurman represented another major step up in competition to rejoin the welterweight elite — and Pacquiao bolted out of the gate to show he was worthy of this matchup between two fighters who owned versions of the WBA welterweight title.

Both fighters started quickly with a series of good-looking exchanges, but Pacquiao changed the bout in an instant. He moved forward to land a left to the body and a right hook that sent Thurman to the canvas with 25 seconds left in the first round.

Thurman got up comfortably while the ecstatic crowd roared, but Pacquiao kept up his superior work for the next two rounds, repeatedly rocking Thurman with a variety of shots. Even when Thurman put together a solid fifth round, he was stunned several times in the final minute and left with blood on his face.

But Thurman gathered himself and soundly beat Pacquiao through the middle rounds, forcing Pacquiao to show off his durable chin. Pacquiao reversed the momentum in the 10th with a series of big shots, including a punch to the body that sent Thurman stumbling away in obvious pain.

Both fighters pushed to the final bell and embraced.

“I knew it was close,” Thurman said. “He had the momentum because he got the knockdown in Round 1. … I wish I had a little bit more output to go toe to toe. My conditioning, my output was just behind Manny Pacquiao’s tonight. Tonight was a blessing and a lesson.”

Thurman called for a rematch, and the crowd vocally approved.

Nearly 25 years after a 16-year-old Pacquiao stepped onto the scales for his pro debut with rocks in his pockets just to make the 105-pound minimum weight, the 40-year-old politician showed he could have several years left in his day job.

Thurman had been eager to retire Pacquiao, but he couldn’t hurt the ageless wonder.

Thurman has held a version of the WBA 147-pound title for six years, but he had fought just once since March 2017, when he edged Danny Garcia to earn two welterweight belts. He sat out the next 22 months with injuries, and he looked rusty and tentative at times in his comeback victory over Josesito Lopez last January.

But Thurman embraced his guaranteed $2.5 million payday and the chance to take on Pacquiao, and he pumped up the promotion with a series of bold statements about Pacquiao’s age, ability and motivation. He even managed to irk the normally placid Pacquiao, who acknowledged that even his mother hadn’t liked Thurman’s trash talk.

Before the bout, Floyd Mayweather got into the ring before the bout to wish both fighters good luck. The retired superstar watched intently from the crowd in the same arena where he beat an injured Pacquiao four years ago. Pacquiao’s trainer, Freddie Roach, has said he hopes Mayweather will come out of rematch for a rematch with Pacquiao.

On the undercard, Cuban welterweight Yordenis Ugás battered previously unbeaten Omar Figueroa Jr. for a decision victory featuring three identical 119-107 scorecards. Caleb Plant also defended his IBF super middleweight title with a dominant third-round stoppage of previously unbeaten Mike Lee.