The 37-year-old Filipino insists he will retire from boxing after the third installment of his rivalry with Bradley, vowing to focus on a political career in his homeland where he is seeking election to the Senate.

While Pacquiao has carefully kept a door ajar to extending his career, he told reporters at the MGM Grand in Las Vegas on Wednesday that he views Saturday's bout as an opportunity to sign off in style.

"It's really important for me to win this fight, to win convincingly," Pacquiao said. "It's part of my legacy”.

Asked if he still retained the killer instinct which helped him win an unprecedented eight world titles at eight different weight classes, Pacquiao said his long absence had served to renew his enthusiasm for the ring.

"I still have that (killer instinct)," Pacquiao said. "I rested almost one year and when I started training for this fight I felt fresh and hungry again, like I did when I first started boxing. It's been good for me. It's good that I had a long layoff”.

"I still have that desire. I love boxing. Boxing is my passion. I grew up on boxing. I started when I was 12 years old, non-stop, until now,” added the veteran boxer. Pacquiao's long-time trainer Freddie Roach said he had questioned whether retirement talk could prove a distraction.

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