I thought I had seen this picture before, so I checked the archives. Don't know if they were "overall" #1 seed, but in the 2000 second round #1 Arizona fell to the #8 Badgers in the second round 66-59.
(And for the record, #1 Bucky beat overall #1 Kentucky 71-64 in the 2016 Final Four, and in 2014, #2 Wisconsin beat #1 Arizona 64-63 in the Elite Eight in OT.)
So this marks the 4th time Wisconsin has taken down a #1 seed. All is not lost, however. They lost to #1 seeds five times, to Missouri in 1994, Mich State 2000, Maryland 2002, Kentucky 2003 and Syracuse 2012.
It has struck me that over the Bennett, Ryan and Gard eras, Wisconsin has had a style of play where they could beat any team, but also lose badly to almost any team when their shots were not falling - like today's Virginia result. Except for the Kaminsky-Dekker years, they never had the talent to be a sure-fire winner in the early rounds. I guess that says something about the coaching.