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]
(..) ...he's nothing to me but an empty seat. It pisses me off, your loyaIty to Spider-Man and not to your best friend. I find him with my father's body, and you defend him. Take it easy. Don't push me. Don't act like you're my friend. You stole M.J. from me. You stole my father's love. (..)2004 Spider-Man 2