The team is looking to 'defend' its national title. [=to win the national title again]
As a U.S. senator, it is my responsibility to 'defend' [='uphold'] the Constitution.
She successfully 'defended' her championship. [=she won the championship again]
(..) wait in a deserted subway station... ...because you got distracted. Ben, sweetheart, honestly... ...I am completely capable of walking home-- You will not defend this boy! - I'm not defending-- - You are! - Listen to me, son. - Yeah, go ahead. You're a lot like your father. (..)2012 The Amazing Spider-Man