There are a few ways to look at games like this one.
One hand, games like this happen to good teams. The NBA is full of players who are in the top 1 percent of the 1 percent of all-world athletes who are good at the game of basketball. At times, even bad teams are going to be able to beat good teams. Guys like Evan Fournier and Bismack Biyombo have big contracts because of their talent. They may not be able to perform at this level every night, but they have it in them.