Of course wins like tonight's are unusual. We've had two top 10 nonconference wins away from home in the last ten years, but those were both neutral site games (vs. #8 Memphis in Maui in 2011, and the famous win at MSG over #4 UCLA in 2008). We've have a few top 10 road wins in recent years, but those have all been conference opponents (mostly Sparty). However, none in the nonconference on the road.
Many Michigan teams don't get a chance to play a top 10 nonconference team on the road, and those that do are obviously heavy underdogs. Interestingly, it looks like our last two such wins are both against Duke. The most recent was December 8, 1996, a 62-61 victory for #7 Michigan over #10 Duke. Of course, that season was vacated by sanctions.
The most recent unvacated road win against a top 10 opponent was #1 Michigan defeating #5 Duke on December 5, 1964. Yes, 1964.
So enjoy tonight, everyone. This is not something you see every decade.