noun
giant-killing; defeating a much stronger opponent
Sports term for an underdog beating a heavily favored opponent; used in contexts like soccer, tennis, and other competitive sports.
その試合はまさにジャイアントキリングだった。
That match was a real giant-killing.
格下のチームが優勝候補を破るジャイアントキリングが起こった。
A giant-killing occurred when the lower-ranked team beat the tournament favorite.