Shane Mosley clinched the interim WBC welterweight title with a unanimous points decision over Luis Collazo in Las Vegas.
Collazo, who recently lost his IBF belt to Britain's Ricky Hatton won just one round as 35-year-old Mosley was awarded a comfortable victory thanks to judges' scores of 118-109 118-109 119-108.
He also put his fellow American down in the 11th round, with Collazo given only the second round by the judges.
Mosley previously held the title from 2000-02 and will progress to full champion status when Floyd Mayweather Jr fights Oscar De La Hoya for the light middleweight crown in May.
Nicknamed ‘Sugar', Mosley had also been competing primarily in the light middleweight division in recent years and has held titles at both that weight and lightweight.
But he said after the fight: ‘It feels good to be a welterweight again. I felt light on my feet.’
The undercard saw Guyana's Vivian Harris become number one contender for Junior Witter's WBC light welterweight crown with a unanimous decision points decision over Juan Lazcano.
Briton Witter successfully defended his title against Arturo Morua last month.
