By Edward Chaykovsky

Top Rank's CEO Bob Arum believes WBO welterweight champion Manny Pacquiao has a much better chance to defeat Floyd Mayweather Jr. in a potential 2017 rematch.

Mayweather sat ringside on Saturday, and watched Pacquiao defeat Jessie Vargas to capture the WBO belt at the Thomas & Mack Center in Las Vegas.

Mayweather retired last September after decisioning Andre Berto. Pacquiao himself retired in April after beating Timothy Bradley in their third fight, but decided to continues his career after winning a senatorial seat back home in the Philippines in May.

Arum gave the rematch a 75% chance of taking place next year. Arum has yet to discuss the possibility of a rematch with Mayweather, but he has a good feeling about the fight coming off.

"I'm guessing [with my prediction of 75%]. I haven't talked to Mayweather yet, but he was at the fight. He seemed to enjoy the fight so I'm optimistic that the fight can happen. He was there and the interaction between him and Manny. Manny looked really good in the fight with Jessie Vargas. I would have to say that it's more favorable than not, that the rematch would happen. But I'm not certain of it and I haven't talked to Floyd or his people yet," Arum told TMZ Sports.

The first fight generated $600 million in revenue and sold 4.6 million pay-per-views. A large number of fans were disappointed. Arum feels the rematch will still draw a lot of interest from the fans. Arum knows the rematch won't sell as much, but he's hoping the number still lands at over 2 million buys.

"I think so. I think Manny really looks a lot better now. I think this time I give my guy Pacquiao a hell of a lot better chance [to win]," Arum said.

"The biggest [pay-per-view of all-time] was of course the first fight. I don't think this will exceed the first fight, but I'm hoping that it will be the second biggest of all-time."