LAS VEGAS - British star Amir Khan made his debut in the welterweight division a successful one on Saturday, winning a unanimous decision over former champion Luis Collazo at the MGM Grand Hotel. The 27-year-old Khan, who was fighting for the first time after a 12-month layoff, knocked Collazo down three times in the non-title fight.Khan looked impressive in the 147-pound (67 kg) division debut, winning on all three judges' scorecards. Two judges scored it 119-104 while the other had it 117-106. "Collazo was very awkward," said Khan, adding he was pleased with the way he made mid-bout adjustments Saturday to beat a difficult opponent. "I think it was great to have that layoff. I needed a break from boxing but at the same time I needed to work on some things."Khan hopes that this win puts him in line to fight Saturday's headliner Floyd Mayweather next. "Definitely, people want to see that fight between me and Floyd," Khan said. "He's fighting guys who are strong, but styles make fights, and I believe my style would cause Floyd a lot of trouble." Khan knocked Collazo down for the first time in the fourth round and then twice in the 10th round in front of a sold-out crowd of 16,268 at the Grand Garden arena.Khan, a former light welterweight world champion, weighed 161 pounds when he stepped into the ring on Saturday, 14 pounds over his weight at Friday's weigh-in. "I am much more comfortable at this weight. It is perfect for me," said Khan of his move up to the welterweight division. Collazo also bulked up for Saturday's fight weighing 16 pounds more than his 147 pound weigh-in weight.The bout was on the undercard of the Mayweather's majority decision over Marcos Maidana in a welterweight world title unification fight. Khan didn't think Mayweather looked his normal self in his win over Maidana and says father time may be catching up to the undefeated world champion. "He is getting older and showing a lot of mistakes that he didn't used to do. It is a great time to catch him," said Khan.Mayweather dodged questions at the post-fight news conference about whether he wants to fight Khan next. Khan's chances of landing the biggest fight of his career later this year also took a hit when Mayweather shook hands with Maidana's trainer Robert Garcia and promised them a rematch.