What's the noun for prizefight? Here's the word you're looking for.
prize
That which is taken from another; something captured; a thing seized by force, stratagem, or superior power.
(military, nautical) Anything captured by a belligerent using the rights of war; especially, property captured at sea in virtue of the rights of war, as a vessel.
An honour or reward striven for in a competitive contest; anything offered to be competed for, or as an inducement to, or reward of, effort.
“Further examinations saw him become first Smith's prizeman and he was elected a fellow of Peterhouse.”
“He graduated in 1850 as second wrangler and Smith's prizeman.”
“He studied at Queens' College, Cambridge and was coached privately by William Hopkins, graduating in 1834 as senior wrangler and first Smith's prizeman.”