Oh, the joys of being a longtime GW basketball fan. LSF (best board name) and too many of us understand too well.
We now, as best I can determine, have the honor of being on the losing end of the biggest upset in men's college basketball this season.
While the Stony Brook loss in MoJo's last season might be to many the most frustrating loss in Smith Center history, the loss to Delaware is arguably worse, especially with all the hype and money spent on this year's team.  After a little research and some help from AI, I found that no team was a bigger favorite (22.5) this season than GW and then lost. 
Here are some huge upsets in recent years, but all from NCAA Tournament.
2023: Purdue favored by 23.5 loses to Fairleigh Dickinson, 63-58
2012: Missouri favored by 21 loses to Norfolk State, 86-84
2018: Virginia favored by 20 loses to UMBC, 74-54

 BTW, the most frustrating neutral site loss I would argue,  was to Iowa in the NCAA Tournament in 1996, where we led by 16 with about 8 minutes to go and lost 81-79.

CC has talked in press conferences about our high  KenPom ranking and being among the best in the A-10. 
It will be interesting to see how the team responds against Florida and, more importantly, whether CC can produce more than a middling A-10 team this season.