Top Rank's CEO Bob Arum, who for many years was the lead promoter of Manny Pacquiao, believes the Filipino superstar would defeat Floyd Mayweather if the two boxers ever came together for a rematch.

Last month, Pacquiao turned back the clock to win a twelve round split decision over undefeated Keith Thurman to capture the WBA welterweight title at the MGM Grand in Las Vegas.

The victory, at 40-years-old, is one of the biggest in Pacquiao's very long career.

Pacquiao parted ways with Arum in 2017, and he is now being promoted by Al Haymon's Premier Boxing Champions.

Arum would like to see Pacquiao go out right now, on a very high note.

"He got the win [against Keith Thurman], he went out on a big note," he told Fighthype.com.

"I would recommend that this is the time for him to hang it up; but listen, he makes his own choices."

In several post-fight interviews, Pacquiao has called for a rematch with Mayweather.

Arum co-promoted Pacquiao's encounter with Mayweather in 2015 - a record breaking event that shattered numerous financial and pay-per-view records.

Mayweather won a twelve round unanimous decision in the bout.

Arum expects a different outcome if they met again.  

"If that fight happens, then it's probably worth it to do because that would be a big, big, big fight,” Arum said. "Manny Pacquiao would win now."

Mayweather retired from boxing in August of 2017, when he stopped UFC superstar Conor McGregor.

The former pound-for-pound king recently took to social media to take shots at Pacquiao.

"I find it real ironic how every time Pacquiao's name is brought up in the media, my name is always attached to it," Mayweather stated.

"This man's entire legacy and career has been built off its association with my name and it's about time you all stop using my brand for clout chasing and clickbait and let that man's name hold weight of its own. For years, all you heard was that 'Floyd is afraid of Manny Pacquiao,' but what's funny is, when we finally fought, I won so easily that everyone had to eat their words!

"All of the so called boxing experts, critics and jealous American 'fan base' either went mute and ran for cover or made every excuse in the world as to why I should give Manny Pacquiao a rematch. My take on all this bulls*** is that y'all are just upset that I broke Rocky Marciano's record and hate the fact that a black, high school dropout outsmarted you all by beating all odds and retiring undefeated while maintaining all my faculties simply by making smart choices and even smarter investments. Ultimately, I will always have the last laugh."