The prospect of a rematch between Floyd Mayweather and Manny Pacquiao is on the cards after the latter enjoyed an impressive return to the ring against former world welterweight champion Jesse Vargas last weekend. The retired champion Mayweather was at ringside as a spectator .Promoter Bob Arum claims that a second fight for Mayweather and Pacquiao is 75% certain to happen."Having invited Mayweather to watch his defeat of Vargas, in which he claimed the World Boxing Organisation welterweight crown, Pacquiao believes there is unfinished business between him and his undefeated rival," the Daily Telegraph in London reported this week."A second contest - in spite of the displeasing aesthetics of the first match which resulted in a boxing lesson from Mayweather - could prove a much better fight," he adds.The main stumbling blocks will be luring Mayweather out of retirement and shoehorning the fight into Pacquiao's busy schedule as he carves out a career as a politician in the Philippines.Mayweather has not fought since retiring last year and he will turn 40 next year. However, he is still said to be in training in Las Vegas and there are several reasons he could be persuaded to take the fight, says Josh Katzowitz of Forbes.One of them is money."Mayweather earned $700-million during his career," says Katzowitz. "But that doesn't mean he doesn't want more of it, and Pacquiao would be his best - probably only - hope for another $100-million payday."A second fight would not create the same buzz as the first, but with one or two exceptions "Mayweather-Pacquiao Two would generate more excitement than any other fight in the sport", he says. "And it would still make plenty of money."Mayweather also has cause to believe he could win, adds Katzowitz.The American will not risk his unbeaten record, "but from the way Pacquiao performed against Vargas, Mayweather should be reassured that beating Pacquiao a second time would be even easier than the first".Arum, who looks after Pacquiao, has added fuel to the fire by saying a rematch is likely despite admitting he has yet to speak to anyone from Mayweather's team...