Juan Manuel Marquez vs Juan Diaz I

Juan Manuel Márquez vs. Juan Díaz, billed as A Battle for the Ages. A Fight for Supremacy, was a boxing lightweight title superfight, for the vacant WBO and WBA lightweight championship, and Marquez's The Ring lightweight title. The bout was held on February 28, 2009, at the Toyota Center in Houston, Texas, United States. Marquez won the fight via technical knockout in the ninth round.

The match was named the 2009 Fight of the Year.