Tennessee is making every defense not named Georgia's look bad this season, and Tigers had to make the trip to Knoxville at a very brutal time. Vols had just gotten pummeled on the road by Georgia, were back home and ready to put on a show to the College Football Playoff committee as they still have a chance of making the four-team bracket. They were determined to put on a show, and they did. The Tigers were not caught off guard. Knowing what's coming and being able to stop it are very different things. Tennessee is just a better team right now, by a lot.
There has been a lot of revisionist history about Heupel. No Mizzou fans were complaining when he left for the head coaching job at UCF. His offense, when it lacks great QB and great receivers, can put a lot of stress on a defense, and that showed at Mizzou. He's gotten better due to his head coaching experience at UCF, where he succeeded, and now he's got a QB and the kind of electric offense that can help recruit the next round of skill players. Guys want to play in his system. The AD at UCF brought him to Tennessee, believing in him, and it worked.
It should not be overlooked that part of Tennessee's newfound success in all sports -- baseball, basketball, football -- has come with finally getting the right balance between athletics department leadership, university leadership and coaches. Mizzou has been in a churn mode for a long time, and it's hard to build much of anything when the faces are always changing.