HOLLYWOOD, Florida – What was supposed to be a relatively easy tune-up fight for Rau’shee Warren turned disastrous Saturday.

Mexican journeyman Francisco Portillo upset the heavily favored former WBA bantamweight champion by unanimous decision in a six-round fight on the non-televised portion of the Omar Figueroa Jr.-Sergey Lipinets undercard. Warren dropped Portillo in the second round, but Portillo got off the canvas and engaged Warren in a dogfight that the huge underdog won on all three scorecards at Seminole Hard Rock Hotel & Casino.

Judges Fernando Barbosa (57-56), Daniel Fitzgerald (58-56) and Michael Ross (57-56) all scored their back-and-forth fight for Portillo. Each judge scored four of the six rounds for Portillo, but Fitzgerald only scored Warren a 10-9 winner of the second round, whereas Barbosa and Ross scored that round 10-8 for Warren.

FanDuel sportsbook listed Warren as a 30-1 favorite over Portillo (18-11-2, 10 KOs).

The 35-year-old Warren, a three-time U.S. Olympian from Cincinnati, had hoped to build his way back toward another 118-pound title shot before ending his career. The former WBA bantamweight champ had won three straight bouts since French southpaw Nordine Oubaali (then 14-0) out-pointed him unanimously to win the then-unclaimed WBC 118-pound championship in January 2019 at MGM Grand Garden Arena in Las Vegas.

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