The 24 point goal is just a statistical measure that the coaches go by. It's not a rule that if the D holds the opponent under 24, they aren't responsible for loss. In this case, they did hold their opponent under 24, but they allowed the opponent take 40 of the 60 minutes to do it. That has a direct impact on the offense's ability to score over 24 points. The fact that they let Mizzou hold the ball for 40 minutes had a direct impact on the outcome of the game.