LAS VEGAS – Oscar Valdez arrived at MGM Grand 14 months ago as a decided underdog against Miguel Berchelt.

That only motivated Valdez to put on the performance that has defined his nine-year professional career. Nogales’ Valdez dominated Cancun’s Berchelt in their fight for Berchelt’s WBC super featherweight title at MGM Grand Conference Center.

Valdez dropped Berchelt once apiece in the fourth, ninth and 10th rounds. He punctuated his splendid display by taking a step back and blasting Berchelt with a left hook that emphatically ended their fight and crowned Valdez as a world champion in a second division.

The 31-year-old Valdez returned to MGM Grand this week to find, despite his impressive victory over Berchelt, that he is an even bigger underdog entering his 130-pound title unification showdown with Shakur Stevenson. MGM Grand’s sportsbook listed Stevenson (17-0, 9 KOs) as a 7-1 favorite on Saturday morning to win a 12-round main event ESPN will air Saturday night as the featured attraction of a three-bout broadcast set to start at 10 p.m. ET.

“It doesn’t offend me at all,” Valdez told BoxingScene.com. “On the contrary, it motivates me. And the reason for that, it’s like my old trainer said, my ex-trainer Manny Robles said, ‘You’re only as good as your last performance in the eye of the public.’ So, my last performance wasn’t my best. On the contrary, I would say it was one of my worst performances I’ve had. On the other hand, Shakur Stevenson’s best performance was his last fight, so that just shows on the bets. But I love it. I love the fact that I’m the underdog. It brings more motivation to me.”

Brazil’s Robson Conceicao tested Valdez during his last fight, which resulted in a 12-round, unanimous-decision win September 10 in Tucson, Arizona. Though Valdez won on all three scorecards (117-110, 115-112, 115-112), Conceicao got off to a strong start and won five rounds on two scorecards.

Valdez (30-0, 23 KOs) partially attributed his uneven outing against Conceicao (17-1, 8 KOs) to distractions caused by his performance-enhancing drug ordeal.

Four weeks before they fought, Valdez tested positive for Phentermine, a stimulant banned by the Voluntary Anti-Doping Association. The Pascua Yaqui Tribe Athletic Commission licensed Valdez anyway because, like all state and tribal commissions in the United States, it adheres to guidelines established by the World Anti-Doping Agency, which permits the use of Phentermine both in and out of competition.

Six weeks after Valdez’s victory, the 24-year-old Stevenson completely controlled his fight against Jamel Herring. The Newark, New Jersey, native eventually stopped Cincinnati’s Herring (23-3, 11 KOs) in the 10th round to win the WBO junior lightweight title October 23 at State Farm Arena in Atlanta.

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