Timothy Bradley remained undefeated with an eighth-round stoppage of Cuban southpaw Joel Casamayor, putting him in position as a possible 2012 opponent of Filipino boxing icon Manny Pacquiao. Referee Vic Drakulich halted the fight with one second remaining in the eighth round after Bradley landed a series of blows that forced Casamayor to take a knee, the third time Bradley had put the 40-year-old down in the fight. Bradley kept his World Boxing Organization junior welterweight crown and improved to 28-0 with his 12th stoppage inside the distance while Casamayor fell to 38-6 with one drawn. The Bradley-Casamayor fight topped Saturday's undercard for Pacquiao's welterweight showdown against Mexico's Juan Manuel Marquez. Rather than take a deal to fight England's Amir Khan in what would have been a unification showdown for the undisputed world junior welterweight crown, Bradley took the Casamayor fight to put himself in position to face Pacquiao. While boxing fans yearn for a megafight deal matching Pacquiao and unbeaten US star Floyd Mayweather in 2012, they might have to settle for Pacquiao facing Bradley with Khan becoming a possible Mayweather foe. Khn, backed like Mayweather by Top Rank rival Golden Boy, will defend his International Boxing Federation and World Boxing Association junior welterweight titles against Lamont Peterson on December 10 at Washington with plans to jointhe welterweight ranks in 2012. Khan has served as a sparring partner for Pacquiao, both of them working with trainer Freddie Roach. Bradley was criticized for a lackluster victory over Devon Alexander last January and switched promoters, inking a deal with Top Rank, which also promotes Pacquiao. Bradley said before facing Casamayor that he needed to look impressive as well as win in order to make his case for a fight with Pacquiao. Early on, that seemed a tough prospect. Casamayor grabbed Bradley repeatedly in the opening rounds, allowing only brief exchanges. Drakulich deducted a point from Casamayor for excessive clinching at the start of the fourth round, forcing a more open style that allowed Bradley to land some solid combinations by the end of the round. Bradley knocked down Casamayor with body blows early in the fifth round and stung the Cuban with a flurry midway into the round. Casamayor went down again at the first exchange of the sixth round, the challenger protesting in vain that it was merely a slip. When Bradley was forced to touch his gloves to the canvas at the end of round seven after a hip bump from the Cuban, it was ruled no knockdown. The end came 2:59 into the eighth round after Bradley landed a flurry that forced Casamayor to one knee. He rose and went to his corner, where Drakulich stopped the fight.