Bracket buster
Bracket buster , as a generic phrase , refers to an American college basketball team , usually from a so-called mid-major school , which upsets a highly ranked team in the NCAA Division I Men's Basketball Tournament and to a lesser extent , the NCAA Division I Women's Basketball Tournament . 
<triplet> NCAA Division I Men's Basketball Tournament <subj> American <obj> country <triplet> NCAA Division I Women's Basketball Tournament <subj> American <obj> country