score an own goal
To earn a point for the opposing team by scoring a goal on one's own net. (Used especially in reference to soccer.) We were never able to regain our lead after Thomas scored an own goal late in the second half.
score an own goal
1 (in football) score a goal by mistake against your own side. 2 do something that has the unintended effect of harming your own interests. informal 2 1991 Brian MacArthur Despatches from the Gulf War Television's mission to explain was taken to its outer limit and at times scored an own goal by developing a bias against understanding.