Gundam Build Fighters

Synopsis

For day three of the tournament, containers with random weapons are placed in the battlefield for the Gunpla Fighters to use in their battle; each contestant is assigned a container number to use. Sei and Reiji are assigned to battle Luang Dallara, who already gave them trouble at the battle royal. Worsening the situation is Reiji's wrist injury from a street fight outside the arena grounds.

(Source: Wikipedia)