By Edward Chaykovsky

Hall of Fame trainer Freddie Roach is predicting a wipeout when Manny Pacquiao challenges WBO welterweight champion Jessie Vargas later tonight at the Thomas & Mack Center in Las Vegas. The fight will headline an Top Rank pay-per-view event.

Vargas captured the vacant WBO title in March with a knockout of previously undefeated Olympian Sadam Ali.

Pacquiao is snapping a short-lived retirement, which he announced in April after dominating Timothy Bradley over twelve rounds in their trilogy fight. Pacquiao captured a senatorial seat the following month back home in the Philippines and by July he was already planning out his fall return.

According to Roach, he barely even heard of Vargas before the fight with Pacquiao came together. Vargas and his new trainer, Dewey Cooper, have done a lot of talking during the weeks of pre-fight promotion - which Roach is confident will backfire when everything is said and done

"I have never seen him on TV, I have never seen him on TV. I forget this guys name every day of my life, come on give me a break. What’s his name? Jessie what? Him and his trainer can go cry after the fight. I promise," Roach told On The Ropes Boxing Radio.

Roach is predicting that Pacquiao will score his first knockout victory since stopping Miguel Cotto in the twelfth round in 2009.  He feels Vargas' inability to punch, lack of speed and inexperience will all be exposed in the contest.

"I predict Manny knocks him out in the late rounds. He can not handle Manny’s speed. He’s too slow and he can’t punch, so he’s not that dangerous a fighter. I’m not impressed," Roach said.