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 also revived his ring career with solid back-to-back victories over Lucas Matthysse and Adrien Broner.

Thurman represented another major step up in competition, but Pacquiao's strong start quieted any speculation that he would suddenly look old in a matchup with an elite welterweight champion.

Thurman's effort was impressive on paper: He landed slightly more punches than the famously active Pacquiao, and his 192 power punches landed were the most by any Pacquiao opponent in his 43 fights that were tracked by CompuBox. But Pacquiao had a dominant jab, and he outworked Thurman in the 12th round, throwing 56 punches to win the round on two judges' cards.

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. Pacquiao won the final round on two judges' cards, while Feldman's 12th-round score for Thurman kept Pacquiao from winning by unanimous decision.

After graciously congratulating Pacquiao, Thurman called for a rematch. The pro-Pacquiao Vegas 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, this middle-aged politician showed he could have several years left in a day job that paid him a guaranteed $10 million on Saturday night.

Thurman had been eager to retire Pacquiao, but he even 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 an active legend. He also pumped up the promotion with a series of bold statements about Pacquiao's age, ability and motivation. Thurman 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 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 retirement 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.