Parsimonious refers to frugality and it also means making a minimum number of assumptions. The sports reference is to not conceding goals.
Here are some mentions of the word in literature.
“Earthly nature may be parsimonious, but the human mind is prodigal, itself an anomaly that in its wealth of error as well as of insight is exceptional, utterly unique as far as we know, properly an object of wonder.”
“You have read Darwin,” I said. “But you read him misunderstandingly when you conclude that the struggle for existence sanctions your wanton destruction of life.” He shrugged his shoulders. “You know you only mean that in relation to human life, for of the flesh and the fowl and the fish you destroy as much as I or any other man. And human life is in no wise different, though you feel it is and think that you reason why it is. Why should I be parsimonious with this life which is cheap and without value? There are more sailors than there are ships on the sea for them, more workers than there are factories or machines for them. Why, you who live on the land know that you house your poor people in the slums of cities and loose famine and pestilence upon them, and that there still remain more poor people, dying for want of a crust of bread and a bit of meat (which is life destroyed), than you know what to do with. Have you ever seen the London dockers fighting like wild beasts for a chance to work?”