LAS VEGAS: British boxer of Pakistani origin Amir Khan defeated Devon Alexander by a unanimous decision in a welterweight fight, using his superior hand speed and strength to dominate the American southpaw for 12 rounds.

The 28-year-old Khan consistently beat Alexander to the punch, jabbing his way to victory in the non-title fight on all three judges' scorecards, 120-108, 119-109 and 118-110.

“I think it was one of my best performances,” said Khan, who looked unscathed except for a welt under his left eye. “I am the best boxer with the quickest hands in the world. I am getting better.”

Khan used his jab effectively to set up combinations that earned him the bulk of points as both fighters made it to the final bell in front of a crowd of 7,768 at the MGM Grand Hotel and Casino.

Khan also showed off his much-improved defensive skills, the result of hooking up with trainer Virgil Hunter in September 2012.

Alexander, who looked impressive in his last fight against Jesus Soto Karass, went into the 12th round needing a knockout to win.

Khan was originally scheduled to fight the American for Alexander's International Boxing Federation welterweight title last December in New York. But the Briton scrapped the bout because he thought he had a chance at landing a bank-breaking dream fight with Floyd Mayweather that never came off.

Alexander then lost the title to Shawn Porter, and Khan's fellow Brit Kell Brook snatched it from Porter in August.

Khan won every round on one judge's scorecard, all but one on a second and all but two on the third card. He connected on 43 percent of his shots, compared to just 20 percent for Alexander.

“I just fought a three-time world champion and proved myself to be a force at 147 pounds,” Khan said. “I think I'm getting better with age. I'm better than I was at 26 and now just starting to hit my peak at 28. I worked very hard and put on one of my best performances.”

Boxing fans the world over are hoping unbeaten Mayweather's next fight is against Filipino superstar Manny Pacquiao, but Khan showed Saturday that he would be a solid opponent if the highly-anticipated “richest fight in boxing history” can't be realized.

“I believe I have earned my shot against Floyd Mayweather,” said Khan, who was fighting for just the second time as a welterweight. “It would be huge and I would walk out with the belt.”

In another welterweight fight at a different Las Vegas venue Saturday, former two division champion Timothy Bradley and Diego Chaves fought to a 12-round controversial draw.

The decision resulted in plenty of boos from boxing fans who thought Bradley deserved the win.