His performance in the speech contest was a home run.

home run 是棒球术语，原意是"本垒打"，指击球手击出球后能跑完所有垒包直接得分的击球。 在非体育语境中，home run 常用来比喻"大获成功"或"非常出色的表现"，强调取得了显著成就或完美结果。