It is my observation (i.e. IMO) that early in the season Freshmen make mistakes at the end of games out of fatigue. They have never been asked to play forty-minute games before, and in particular to play hard at both ends of the court. And when they tire, they revert to bad habits and reliance on athleticism that is no longer that far superior to the competition. That was fully on display last night.
As the season progresses, they get into "college shape" and their talent advantage comes to the forefront, so the team soars up the bell curve. So, UK's youngest teams sometimes dominate the SEC regular season, and even the conference tourney.
And then they hit a wall. It is not unlike the wall many rookie RBs hit in the NFL after 12-13 games because they have never played more than that, nor been hit so hard, so often by NFL level athletes. In basketball the same happens with freshman who have been banging with older, stronger upperclassmen for 30+ games. And so, they are worn down and start missing shots and getting pushed around on D in ways that weren't seen ten games back when the team was dominating. It is the reason (IMO) that teams full of 22-year-old men are so successful in the tournament. And that is how teams lose in the closing minutes to K State, Auburn and even St Peter's teams whose leaders are physically able to weather the long season better.