In Adventure Mode, your racket has a durability meter. Each time you block a Zone Shot or Special Shot, your racket takes damage. If your racket's durability reaches zero, it breaks, and you lose a life. You start with three rackets. To prevent racket breaks, use Trick Shots to return Zone Shots without taking damage, or perfectly time your blocks. Conserving your rackets is crucial for surviving challenging missions and boss battles. Pay attention to the racket icon near your character's portrait.
