He defeated the former world champion in a stunning match.

defeated 是动词 defeat 的过去式，defeat 的意思是"击败、战胜"。这个词由前缀 de-（表示"去除、剥夺"）和词根 feat（来自拉丁语 factum，意为"完成的事"）组成，字面意思是"使对方的成就失效"，即"击败"。