Is expiation (kaffarah) obligatory for someone who swore, saying: "By Allah, you will not concede more than five goals," or "By Allah, I will not allow you to concede more than five goals," and then exactly five goals were conceded?

Expiation becomes necessary upon breaking a binding oath. The oath is restricted by what the swearer himself has restricted it with. So, if what was sworn upon did not occur, or occurred against the swearer's will, then no expiation is due from him.