Carlos Ocampo cannot believe how one defensive mistake has essentially made many boxing fans dismiss him as an overmatched opponent that has no chance to upset Sebastian Fundora.

The Mexican veteran senses that his only loss, a first-round knockout against Errol Spence Jr. four years ago, is the only thing boxing observers care to remember about his 10-year professional career. Such widespread doubt about his prowess has motivated Ocampo to knock off the heavily favored Fundora in their “Showtime Championship Boxing” main event Saturday night at Dignity Health Sports Park in Carson, California.

“I’m definitely feeling underestimated,” Ocampo said during a virtual press conference recently. “And it’s funny how one mistake, just one mistake that I made four years ago, can shape the perception that people have of me right now. And I can tell you I’m a completely different person. And you’re gonna see how I have matured both physically and mentally, and the fans are gonna have a great show from me, and actually from both of us, during a great fight that you’re not gonna wanna miss.”

The 26-year-old Ocampo has won each of his 12 fights since Spence stopped him with a body shot late in the first round of their 12-round fight for Spence’s IBF welterweight title in June 2018. Ocampo, who was the mandatory challenger for Spence’s IBF belt, let his guard down toward the end of the opening round, which enabled Spence (28-0, 22 KOs) to land a left to his exposed body.

Referee Laurence Cole counted to 10 before Ocampo could attempt to get up from his gloves and knees at Ford Center at The Star in Frisco, Texas.

The 5-foot-10½ Ocampo moved up to the junior middleweight limit of 154 pounds in the fight after he lost to Spence. Canada’s Mikael Zewski (35-3, 23 KOs), whom Ocampo beat by ninth-round TKO on March 25 in Trois-Rivieres, Quebec, is the most noteworthy name on Ocampo’s list of junior middleweight conquests over the past four years.

“Not only do I feel stronger [in the 154-pound division], but I feel faster as well,” Ocampo said. “So, I feel like this weight fits me like a glove, and I’m ready to show why.”

In Fundora, Ocampo will encounter an ever-developing opponent who has shown he is more than just a fighter who is unusually tall for their division. The 6-foot-6 Fundora demonstrated remarkable resolve in his most recent appearance, when he got up from a seventh-round knockdown and stopped Erickson Lubin (24-2, 17 KOs) after the ninth round of a surefire “Fight of the Year” candidate April 9 at Virgin Hotels Las Vegas.

Fundora (19-0-1, 13 KOs) will defend the WBC interim super welterweight he won by beating Lubin when he meets Ocampo (34-1, 22 KOs).

Two title fights will precede Fundora-Ocampo as part of Showtime’s tripleheader Saturday night (10 p.m. ET; 7 p.m. PT).

The Dominican Republic’s Carlos Adames (21-1, 16 KOs) and Mexico’s Juan Macias Montiel (23-5-2, 23 KOs) will fight for the WBC interim middleweight title in the network’s 12-round co-feature. Argentina’s Fernando Martinez (14-0, 8 KOs) will make his first defense of the IBF junior bantamweight title against Filipino southpaw Jerwin Ancajas (33-2-2, 22 KOs), who will try to win back the 115-pound championship he lost to Martinez in an immediate rematch of their February 26 bout at The Cosmopolitan in Las Vegas.

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