1000000%. Jimmy Johnson said a variation of this probably a billion times: You simply cannot get your team "up" more than a few times a year.
No matter who you are. He was speaking about himself, but it goes for every team pretty much ever. At some point, you're not going to play your best. I have no way to quantify it...how it happens, why it happens, when it'll happen, etc. But it does. Always. So, as a coach, you do what you can to get your A+ game out of your team, but you have to understand you're only getting that every so often. You have to find a way to win with your B game or your C+ game. That's what great teams do. And it’s why I find it so comical when fans cry that their favorite team doesn’t blow out everyone they play. Very, very, very few teams do.