Two judges scored the fight 116-112 for Pacquiao, while a third saw it as a 118-110 win for the Filipino.
In their previous fight, Bradley was awarded a split decision victory that many observers felt Pacquiao had won clearly.
“He threw a lot of punches and I didn’t want to be careless,” said Pacquiao. “In the second half of the fight, I listened to my corner and they told me to work on the timing of my punches.”
Pacquiao added that his trainer Freddie Roach “told me to make adjustments and I did. Bradley was wild on the outside so I took it to the inside.”
The early rounds of the fight were explosive, with Pacquiao the aggressor and Bradley looking to land big counter right hands as the Filipino moved forward.
A wild third round saw both men exchanging vicious shots, a pair of lefts from Pacquiao being followed by an uppercut and a right hand from Bradley and a series of ripping body shots by the American.
Through five, Bradley (31-1, 12 KOs) appeared to be on top and Pacquiao looked uncertain how to land cleanly without exposing himself to big counters.
In the sixth, however, the momentum shifted.
Bradley’s output suddenly dropped and Pacquiao (56-5-2, 38 KOs) adjusted his style to throw fast combinations and move out of the way before Bradley had the chance to load up.
The seventh may have been the Filipino’s most dominant round, as he pinned Bradley to the ropes and unleashed flurries.
Bradley beckoned him on, daring him to attack, and Pacquiao paused warily before resuming his assault and landing a hard left hand that stunned his foe.
Bradley continued to have his moments, notably in the ninth round when he landed some hard combinations to Pacquiao’s chin to stem the challenger’s assault, but his punches were more ragged and wild, while Pacquiao’s were shorter and sharper.
Bradley said he had been going for the knockout.
“I tried. I really tried,” he said. “I wanted that knockout. Manny’s a great fighter, maybe one of the best ever. I lost to one of the best.”
It was the first defeat of Bradley’s career.
(Editing by Peter Rutherford)