Timothy Bradley remained undefeated with an eighth-round stoppage of Cuban southpaw Joel Casamayor on Saturday to maintain his hopes of a possible bout with Filipino icon Manny Pacquiao. Referee Vic Drakulich halted the bout 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. But Bradley's hopes to be the next man on Pacquiao's hit list dimmed when the Asian southpaw struggled to a controversial majority decision over Mexican Juan Manuel Marquez, who is in line for a May rematch if he does not retire. And with fight fans worldwide still hoping that a Pacquiao megafight against unbeaten US star Floyd Mayweather can be made, Bradley's place in line might be further back than he would like, even though he and "PacMan" are both promoted by Bob Arum. Casamayor grabbed Bradley repeatedly in the opening rounds, allowing only brief exchanges until Drakulich deducted a point from Casamayor for excessive clinching at the start of the fourth round, forcing a more open style. "What saved that fight was the referee," Arum said. "That was really intelligent." Bradley knocked down Casamayor with body blows early in the fifth round and Casamayor went down again at the first exchange of the sixth round. The end came in round eight as Bradley landed a flurry that put Casamayor on one knee. "Was it a scintillating fight? No," Arum admitted. "But he did what he had to do." That might not be good enough to earn a place opposite Pacquiao. Bradley said he needed to look impressive in winning after coming off a lacklustre win over Devon Alexander last January. But it might have Bradley thinking twice about fighting England's Amir Khan. Rather than take a deal to fight Khan in what would have been a unification showdown for an undisputed crown, Bradley joined Arum and put himself in the Pacquiao line. Khan, backed like Mayweather by Arum rival Oscar de la Hoya, will defend his International Boxing Federation and World Boxing Association junior welterweight titles against Lamont Peterson on December 10 at Washington. Bradley said this week he would face Khan "when the time is right."