This happened to me a few times as well. Score is tied, opponent turns ball over, I counter with 5 hungry attackers on the 87th minute, and boom my opponent quits, and the game doesn't count.

EA sucks. If an opponent quits while he's winning 10-0, tied, or losing 10-0, he should automatically get the loss, period!
He quit, and what happens to quitters? They lose... But not in this game,,,, lol