The Ultimate Fighter 5 winner Nate Diaz (10-4) will get a chance to break out of an 0-2 slump when he tangles with Melvin Guillard (22-7-2) in a lightweight match up at UFC Fight Night 19 at the Cox Convention Center in Oklahoma City, Okla., on Sept. 16, 2009.

Diaz is coming off a disappointing unanimous [...]