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 "Derrick Gainer"): Derrick "Smoke" Gainer (born August 22, 1972, in Pensacola, Florida) is a US born boxer who started out in the featherweight division and now fights in the lightweight division.
Relevant evidence: No