UNCASVILLE, Connecticut – Sampson Lewkowicz laughed as he recalled how skeptics reacted when Jeison Rosario’s promoter promised them he would walk into Julian Williams’ hometown and knock out the heavily favored defending champion.

Philadelphia’s Williams was a 30-1 favorite, yet that didn’t stop the bigger, stronger Rosario from overwhelming him January 18 at Temple University’s Liacouras Center. Rosario hurt Williams badly during the fifth round and beat him by technical knockout to win the IBF, IBO and WBA 154-pound titles.

The Dominican Republic’s Rosario is an underdog again against Jermell Charlo, but Lewkowicz predicted that he’ll stop another favored fighter Saturday night at Mohegan Sun Arena.

“I believe that he will stop Charlo by the 10th round or earlier,” Lewkowicz told BoxingScene.com. “This kid [Rosario] is so hungry that I have no doubt that he will win this fight. It was the same thing I said, and everybody told me I’m crazy, when I said he would knock out Julian Williams within six rounds. It’s a fact that he will win [against Charlo].”

Houston’s Charlo (33-1, 17 KOs) is regularly listed as at least a 4-1 favorite over Rosario (20-1-1, 14 KOs) ahead of their 12-round title unification fight. Showtime Pay-Per-View will televise Charlo-Rosario as the main event of its second three-bout block Saturday night (7 p.m. ET/4 p.m. PT; $74.95).

The 30-year-old Charlo has lost only a controversial, 12-round unanimous decision to Tony Harrison in December 2018 at Barclays Center in Brooklyn. Charlo came back to knock out Detroit’s Harrison (28-3, 21 KOs) in the 11th round of their rematch last December 21 at Toyota Arena in Ontario, California.

In the 25-year-old Rosario, Charlo will encounter a hungry, young champion whose commitment to training and fighting differently than earlier in his career has immensely improved him.

“He turned around his life 360 degrees,” Lewkowicz said. “He went from a guy who thought that one punch would make the difference, to a guy who chops the tree. In this fight, I expect he’ll chop the tree on Charlo.”

Lewkowicz also senses Rosario will benefit from Charlo’s overconfidence. Charlo repeatedly has stated his respect for Rosario and his upset of Williams (27-2-1, 16 KOs, 1 NC), but Lewkowicz doesn’t believe the WBC super welterweight champion.

“To me, he is totally underestimating Jeison, and he will pay the price for that,” Lewkowicz said. “The champion doesn’t lose because he is less than the challenger. It’s because mentally he has something in his mind that will not happen.

“I like Charlo very much. He’s always respectful with me. But now I feel he’s not so respectful toward my fighter. He needs to remember Rosario is the IBF and WBA champion.” 

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