Undefeated Floyd Mayweather, nagged by legal woes that could send him to prison, ends a 16-month layoff on Saturday by fighting Victor Ortiz for the World Boxing Council welterweight title. The all-American showdown could set the stage for Mayweather to finally face Filipino star Manny Pacquiao, provided "Pac-Man" defeats Mexico's Juan Manuel Marquez in November, next year in a bout that fight fans have sought for years. "I believe in my skills. I believe in my talent," Mayweather said. "This fight will not go the distance." It also could mark Mayweather's farewell, with a possible sentence of 34 years behind bars if convicted on all charges in a domestic violence dispute from last September involving former girlfriend Josie Harris. "He's done," Ortiz said. "I don't care what he brings. He was done when he signed to fight Victor Ortiz. America wants to see change. Change is coming soon." Mayweather, 41-0 with 25 knockouts, has not fought since beating Shane Mosley by unanimous decision in May of last year but is confident he can handle champion Ortiz, who at 24 is 10 years younger than the challenger. "I've fought them all, never backed down, stayed focused and was always at my best," Mayweather said. "I don't have to brag, I don't have to boast. I'm going to go in there and execute the game plan." Southpaw Ortiz, 29-2-2 with 22 knockouts, won his first world title five months ago with a unanimous decision over previously unbeaten Andre Berto. "I am going to teach you what it's like to have a loss on your record," Ortiz said to Mayweather in the final pre-fight news conference. "I'm going to hold my hands up and I'm going to put you on your ass." Ortiz dismissed Mayweather's perfect record, saying, "41 of those fighters were not me, 41 of them couldn't move like me. "Floyd is a good fighter but I've always thought he wasn't great. I'm not impressed and I'm not going to hold any respect like his 41 victims." The undercard features a showdown for the vacant World Boxing Council super lightweight crown between Mexicans Erik Morales and unbeaten Pablo Cesar Cano. Morales, 51-7 with 35 knockouts, has not held a world title since 2004 but hopes to climb back to the top at age 35. Since unifying the WBC and IBF super featherweight crowns in 2004, Morales has lost six of 10 fights, his most recent bout a majority-decision loss to Argentina's Marcos Maidana last April for the WBA interim light welterweight title. Cano, 22-0 with one draw and 17 knockouts, receives his first title bout at age 21 as a last-minute replacement for Argentina's Lucas Matthysse, who dropped out last week with a viral infection.