He delivered a knockout blow to all of his rivals.

他彻底击败了所有对手。

《柯林斯英汉双解大词典》

Kentucky's waning tobacco industry could receive a knockout blow if as many as 164 nations adopt a treaty effectively banning cigarettes made from burley tobacco.

如果164个国家都通过一项条约有效禁止白肋烟烟叶制成的卷烟，那肯塔基正在衰退的烟草行业将会受到致命的打击。

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"It's a big step for our maturity, " Kobe Bryant said after helping the Lakers apply the knockout blow by scoring 14of his 31 points in the fourth quarter in Game 4 on Monday night in Denver.

“这是我们成长中的一大步。”科比在周一与掘金的第4场比赛结束后表示。他在这场比赛的第4节拿下了全场31分中的14分，帮助球队获得胜利。

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So in that sense there's the potential for a knockout blow on March 4th.

NPR: Day of Reckoning Ahead for Clinton, Obama

The Romney campaign, looking to score a knockout blow, had devoted last-minute resources to Alabama and Mississippi.

WSJ: Santorum Wins Alabama, Mississippi Primaries

In a sign of their growing power, dads out to end the stereotype recently scored a knockout blow against a pair of TV ads.

CNN: June 15, 2012 -- Updated 1120 GMT (1920 HKT)