功败垂成
a slip betwixt the cup and the lip.
a flash in the pan.
eg: tom is disqualified at the final round, a slip betwixt the cup and the lip.
中英俚语俗语来源：汉书：“垂成之功，败于一日。”
同义词：功亏一篑 look back from the plough.
反义词：一蹦而就 at one stroke.
