MINNEAPOLIS: Rances Barthelemy dethroned International Boxing Federation super featherweight champ Argenis Mendez with a controversial second round knockout on Friday at the Target Center arena. The 27-year-old Cuban boxer kept his undefeated record intact as he improved to 20-0 with 13 knockouts. Barthelemy sent Mendez to the canvas late in the second round with two hard lefts. It was the first time champion Mendez had been knocked down in his career. Barthelemy then used another stinging left and a combination of punches, as the bell sounded to end the second round, which floored Mendez again. Referee Pete Podgorski counted Mendez out to end the fight.