One of the most accomplished trainers in boxing history doesn’t just think Jermell Charlo will upset Canelo Alvarez on September 30.

Freddie Roach predicted that Charlo will become the first fighter in 64 professional fights to beat Alvarez by knockout. Manny Pacquiao’s longtime trainer has seen enough deterioration in the 33-year-old Alvarez to believe that the hard-hitting Charlo can stop the Mexican icon, even though Charlo has made a two-division, 14-pound jump up in weight for this Showtime Pay-Per-View main event September 30 at T-Mobile Arena in Las Vegas.

“Canelo has had an outstanding career,” Roach told a small group of reporters. “And even though I had Gennadiy Golovkin winning their first two fights, I was impressed with the way Canelo fought him. If Charlo was fighting the version of Canelo before he fought Golovkin, I would favor Canelo. But that’s not the case. This version of Canelo will not be able to handle Charlo.”

The 6-foot Charlo (35-1-1, 19 KOs) has been a knockout puncher throughout his two reigns as a 154-pound champion.

The 5-foot-8 Alvarez (59-2-2, 39 KOs) has shown a granite chin, though, throughout his 18-year professional career. Whereas Charlo will make his 168-pound debut, Alvarez is 7-0, including four knockouts, in super middleweight matches and was never hurt in either of his light heavyweight title fights against Sergey Kovalev and Dmitry Bivol.

Roach still feels the remarkably durable Alvarez will have a lot of trouble dealing with Charlo’s strength in their 12-round fight for the Guadalajara native’s IBF, WBA, WBC and WBO 168-pound championships. The Wild Card Boxing Club founder realizes that Alvarez is a 4-1 betting favorite, yet he is certain Houston’s Charlo is ready mentally and physically to shine in the biggest fight of his 15-year pro career.

“I love the attitude that Charlo brings into the ring,” Roach said. “He’s mean and defiant, and better yet, he backs that attitude up with his talent. He cannot be intimidated. He has a great chin and doesn’t get fazed by getting hit. Charlo is downright vicious inside the ring.

“And while both men can fight, I think Charlo will have too much firepower for Canelo to handle, especially at the higher weight. Canelo needs to stay away from Charlo’s left hook. The question is, can Canelo stay away from Charlo’s left hook? I don’t think he can, which is why I’m picking Charlo by stoppage. I can’t wait for this one.”

Keith Idec is a senior writer/columnist for BoxingScene.com. He can be reached on Twitter @Idecboxing.