Junior welterweight contender Lamont Peterson launched a vicious 12-round attack to the head and body of Victor Cayo, dropping the Dominican Republic native to his knees for a full 10 count in their IBF 140-pound title eliminator at The Cosmopolitan in Las Vegas on ESPN's Friday Night Fights.
In victory, the 27-year-old Washington, D.C., native improved to 29-1-1 with his 15th knockout, dropping the 26-year-old Cayo to 26-2, with 18 stoppages.
Referee Kenny Bayless counted out Cayo at the 2:46 mark of the final round as Peterson earned a mandatory shot at Amir Khan, who added the IBF belt to the WBA strap that he already owned with a fifth-round knockout of Zab Judah on July 23.
Peterson was last in the ring in December, when he rose from a pair of second-round knockdowns to salvage a 10-round majority draw against hard-hitting Victor Ortiz, the present WBC welterweight titleholder.
Peterson had a chance to face Khan in February before talks for an April challenge to Khan's WBA belt broke down over money and a rematch clause. Khan moved on and defended his belt by technical decision over Paul McCloskey in the UK.
Cayo had a two-fight winning streak coming in, having scored stoppages in the second and first rounds, respectively, since he was stopped in the sixth round by Marcos Maidana in March of 2010.
Peterson's initial title shot was in December of 2009, when he lost a clash of unbeatens by unanimous decision to Tim Bradley in December of 2009.