Manny Pacquiao's trainer Freddie Roach believes his charge will stop Conor McGregor inside six minutes if they fight next year.
Both fighters have claimed they will clash in the Middle East in what would be McGregor's second professional boxing fight.
His first ended in the 10th round when he was stopped by Floyd Mayweather.
And Roach believes Pacquiao would have an easier night than he did against Ricky Hatton in 2009 when he delivered a sickening KO in the second round.
"If this is true, Manny Pacquiao will have an easier time with you, Conor McGregor, than when he fought Ricky Hatton, said Roach."
McGregor was the first to 'announce' the fight when he tweeted about it on Friday night.
Pacquiao then issued a statement to say part of proceeds from the fight will go to coronavirus victims in the Philippines.
Both fighters are "getting ready for this one epic last boxing fight," said Jayke Joson, special assistant to Pacquiao, who is also a Philippine senator.
"We don't deny it," Joson said of the former UFC featherweight and lightweight champ's tweet.
McGregor announced on Twitter in June that he was retiring from the sport for the third time. He first quit the sport in April 2016 and in March 2019, he again announced he was hanging up his gloves, but on both occasions the retirements were short-lived.
Negotiation between the two camps "is now starting to move on", Joson said, adding a "huge portion" of Pacquiao's earnings would go to those who were affected by the pandemic.
Pacquiao, 41, is the only man in history to hold world titles in eight different divisions.
He defeated Keith Thurman to win the WBA welterweight world title in July and was due to take on Mikey Garcia before the coronavirus crisis.
