Question: What was the nationality of the WBA titleholder that Derrick Gainer lost to in a unanimous decision since his defeat to Juan Manuel Márquez?
Sentence (from "Rafael Márquez (boxer)"): He is a two-time world champion in two weight classes, having held the IBF bantamweight title from 2003 to 2007; and the WBC, "Ring" magazine, and lineal super bantamweight titles in 2007.
Relevant evidence: No