瓮中之鳖

wèngzhōngzhībiē

[be bottled up like a turtle trapped in a jar; be hopeless like a rat in a hole] 处于瓮罐内的鳖。 比喻形势对一方极有利, 另一方则处在受制地位

敌人已成瓮中之鳖, 我军稳操胜券