The Cowboys' defense held the Bills' offense to 3 points in that game. That was the only reason Dallas was able to overcome a 49.9 rating by their QB. A 66.7 rating means the passing game put the team in a bad situation. When you win a game with that kind of passing performance, it almost always means your defense excelled. I'd give the QB credit for playing well late in a close game, but I wouldn't assign him the victory just because he's the QB.