Manny Pacquiao's trainer, Freddie Roach, conceded Juan Manuel Marquez deserves a rematch following their WBO welterweight title fight on Saturday.
Pacquiao won a majority decision in Las Vegas, despite Marquez dominating much of the action in their third fight.
"[Marquez] has given us problems three times now," said Roach. "I do think he deserves a rematch first.
"I thought Manny edged it. It was the kind of fight I don't want to do again but I think we have to."
Philippine superstar Pacquiao had been widely expected to win his third fight against his Mexican rival in convincing fashion and then set his sights on American legend Floyd Mayweather.
However, the questionable outcome also left Pacquiao mulling over a fourth fight with the 38-year-old Marquez.
Asked if he would consider another match, Pacquiao, 32, said: "Any time, any time. I am a fighter and my job is to fight in the ring."
As for Mayweather, seven-weight world champion Pacquiao added: "Well, let's get it on. Make the fight happen and let's give people a good fight."
Five-weight world champion Mayweather had been expected to fight Pacquiao last year before negotiations collapsed over the American's demand for random drug testing.
"I hope that fight does happen," said Roach. "I think it would be the best fight in the world and I would love to see it."
Marquez, who was outclassed by Mayweather over 12 rounds in a non-title welterweight bout two years ago, felt Pacquiao would struggle against the American.
"Commercially speaking it would be a huge fight but boxing is about styles and the style of Mayweather will get very complicated for Pacquiao," said Marquez.
Marquez, who called Saturday's decision "a robbery", drew his first fight with Pacquiao in 2004 and lost the second in 2008, although many observers believed he won both encounters.