By Edward Chaykovsky

Freddie Roach, who trains eight division champion Manny Pacquiao, believes a superb knockout victory over Jessie Vargas will guarantee a 2017 rematch with retired pound-for-pound king Floyd Mayweather Jr.

Pacquiao will challenge WBO welterweight champion Jessie Vargas later tonight at the Thomas & Mack Center in Las Vegas. The fight will be carried by Top Rank Pay-Per-View.

Vargas was at one time promoted by Mayweather before jumping ship to Top Rank, who also handle Pacquiao.

Mayweather won a twelve round decision over Pacquiao last May in their highly anticipated mega-fight. The fight failed to live up to the hype, but it broke every financial record in boxing - including a monster buyrate of 4.6 million on pay-per-view.

Mayweather retired with his perfect 49-0 record last September after dominating former champion Andre Berto over twelve rounds of action.

In the opinion of Roach, Mayweather is fishing for a rematch with Pacquiao - and the veteran coach believes that knocking out Vargas in style may seal the deal on that fight.

"Mayweather did stop by my gym a couple of months ago twice, just hanging around, just wanting to watch the boxing. I think he’s fishing for a rematch with Pacquiao and hopefully that’s what will happen. Being impressive in knocking out Jessie Vargas I think will guarantee us this fight,: Roach told .

"If Mayweather thinks Jessie Vargas can knock out my guy, he’s wrong, but we will see, I mean he’s being trained by an amateur and that’s all I have to say about him."

Pacquiao himself had retired from boxing in April. He announced his return to the sport only a few months later.

How long can he go? Roach could see him fighting for a few more years.

"I could see Manny Pacquiao fighting for a couple more years. The way he trains and his dedication, it hasn’t changed, he hasn’t lost a step yet. Same speed, same power, Manny Pacquiao is the hardest worker I ever seen and he still is," Roach said.