It wasn't a mistake. He's a professional and knows exactly where that line is for a first down. This wasn't some mental lapse. Look at the defender. He quit going after Ingram so the first was easy to get.
Look at the score. When it was 16-10 it was easy to see that the Bucs would win by 1. Everyone bet against Andy Dalton in Prime time. They lost. Those that took Saints ml lost. Vegas made out like a bandit. Prime time fixed game.