"This fight was all for the people and the families that were affected by the typhoon," he said after proving far too strong for Mexican-American Brandon Rios at Macau's Cotai Arena.
The typhoon which struck Southeast Asia killed at least 5,200 people and injured about 23,000 others in the Philippines. It has left about 11million people homeless.
Pacquiao - known as the "Fighter of the Decade" after becoming the first and only boxer to win world titles in eight different divisions - spoke to Young Post at The Venetian Macao about what motivates him to keep on fighting.
Last year Forbes magazine named Pacquiao the world's second highest-paid sportsman, with total earnings of US$62 million (US boxer Floyd Mayweather was top on US$85million; David Beckham was eighth on US$46 million). So it's clearly not a need for money that keeps him lacing up his gloves.
It's not as if he doesn't have other interests, either: Pacquiao has been a politician since his election to the House of Representatives in 2010.
The answer may be lie in the ring. Last year he lost two fights in a row for the first time; in June he lost his WBO welterweight title; then in December he was knocked out in the sixth round of another bout.
Victory on Sunday for Pacquiao, who turns 35 next month, secured the vacant WBO international welterweight title and, more importantly, helped him to regain his boxing reputation.
"This is not about my comeback," he said. "My victory's a symbol of my people's comeback from a natural disaster and natural tragedy. I'm very happy God answered my prayer.
"It was very difficult for me not to visit the ravaged areas; I was in the middle of training and wanted to go, but I couldn't.
"I was just praying for them and sent my staff there to bring help and relief goods. I plan to go there as soon as possible.
"In the beginning I wanted to show everybody the real Manny Pacquiao and use my boxing skills. I think I proved I still have them."
He was certainly much too quick, clever and powerful in the ring for Rios, 27, during their one-sided 12-round contest.
Pacquiao says his country always inspires him when he is fighting. "I'm always motivated to fight because I want to make people happy and bring honour to my country," he said. "My countrymen are sitting by, giving me inspiration to do everything I can do to win the fight."
However, he was asked if the destruction in the Philippines, caused by the typhoon, had motivated him more than normal for this comeback fight.
"Exactly, that's right," Pacquiao said. "To all the people and families affected by this storm - this fight is for you."