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]
(..) Oh, come on. She's nice. What? You know... You know, not everybody went to Yale. It was just a pseudonym, for Christ's sake. Why do you have to defend her? Well, why do you have to point out how stupid everybody is all the time? I thought it was funny. Forget it. Hey, John, we gotta go. Oh. Yeah. (..)2003 Lost in Translation