Sydney - A rematch between Floyd Mayweather and Manny Pacquiao could be on the cards if the legendary Filipino boxer wins his bout against Australian challenger Jeff Horn this weekend, his trainer said on Tuesday.
Pacquiao, who was outpointed by Mayweather in the "Fight of the Century" two years ago, will be the strong favourite when he defends his world title against the unbeaten Horn in Brisbane.
But the Horn fight could be critical to whether the "Pac-Man" secures another superfight with his American rival, Freddie Roach told reporters in Brisbane.
"He (Horn) can derail us really badly. Manny is, I think, i a must-win situation. He wants a rematch with Mayweather," Roach said.
"And I mean to get Mayweather you have to look good against Jeff Horn, he has to look good, he has to be impressive.
"I think there is a lot riding on this fight and I feel Manny has to look really good in this fight and the way the training camp went, I think he will."
Pacquiao was coy about a possible rematch, stressing that his focus was on the World Boxing Organisation welterweight title fight against 29-year-old former schoolteacher Horn at Brisbane's Suncorp Stadium.
"If there's a chance, why not. I'm willing, but let's focus first for this fight," the 38-year-old eight-weight world champion told reporters when asked about fighting Mayweather again.
"We don't want to underestimate Horn thinking about another fight, this fight is not done yet."
Pacquiao, 38, briefly retired last year before making a successful comeback against Vargas in November, and is juggling boxing with his duties as a senator in the Philippines.
Boxing legend Mayweather, 40, is coming out of retirement to fight mixed martial arts star Conor McGregor in August.