I think it's a little disingenuous to believe that simply being 19 years old exempts them from fatigue, even at a minor level, especially when the team they are playing against is a team of 19 year olds who weren't subject to playing 3 games in 5 days. There has to be some advantage for Tennessee in that aspect, however large or small is a matter of debate.
That level of fatigue for Mizzou is perhaps neutralized by the idea that Tennessee had to travel to Fayette-Nam on Friday, play against Arkansas, then travel back to Knoxville on Saturday, quick turnaround and travel to Columbia, MO on Monday, and play on Tuesday. Unsure whether classes at Tennessee are out for President's Day, or not, but it would have been nice for Tennessee to be able to travel to Mizzou directly from Arkansas and eliminate a lot of the back and forth.