Clemson's D can keep them in the game, but they will need to game plan to keep the kid in the pocket and disguise some coverages. You have to force him into a mistake and cannot miss the picks or fumbles when they happen like Washington did. Playing them straight up will get you killed as will playing them from behind since they will grind you with that road grader of an offensive line.
The offense will have to score fast and often and keep Watson moving around. I would not call it a weakness because there is not many times it has happened this year, but Bama does struggle with mobile quarterbacks that they cannot keep contained. Even Browning had success when he picked his spots correctly.
I like Clemson in this one, but do not bet the house on it.