AMIR KHAN has vowed to "earn" a bout with boxing's pound-for-pound king Floyd Mayweather by comprehensively beating Luis Collazo in Las Vegas.

Khan appeared set for a showdown with the undefeated Mayweather tonight, but the American instead chose to fight Marcos Maidana in a world title unification bout.

But rather than sulk, the 27-year-old from Bolton agreed to star on the undercard.

And he will make his welterweight debut against Collazo, a rugged southpaw from New York who has won his last four fights, which includes a shock second-round knockout victory over former 147lb world champion Victor Ortiz.

While Khan is refusing to look past the 33-year-old, he hopes a dazzling display will put him in the shop window for a megabucks showdown with Mayweather.

"As long as I put on a great performance I'll earn that shot at fighting Mayweather," he said.

"But, to be honest, I'm not looking past Collazo. I need to win this fight and take it from there.

"It's going to be a hard fight, but I think I have all the tools to beat him."

Question marks over Khan's ability to take a punch continue to dog him, but he insists he has been honing his technique with trainer Virgil Hunter and that his time away from the ring may prove to be a blessing in disguise.

"The hand speed and movement is always going to be there, but there are a lot of new things you will see," he said.

For his part, former WBA champ Collazo is determined not to be another stepping stone on Khan's path to a potential shot at Mayweather.

And he is keen to upset the odds in a bout that will be contested for the lightly-regarded WBC Silver welterweight title.

He told Khan: "Welcome to the welterweight division. Once the bell rings you're going to see the best Collazo you've ever seen."