Question: What is the nationality of this professional boxer who lost to Breidis Prescott in a upset match in 2008 that was heavily favoured toward him?
Sentence (from "Amir Khan (boxer)"): He is a former unified light-welterweight world champion, having held the WBA (later Super) title from 2009 to 2012, and the IBF title in 2011.
Relevant evidence: No