Louisville's 78-63 opening win over Jacksonville State means that half of the No. 2 seeds have advanced. Arizona easily won against North Dakota on Thursday.

While a top seed has never lost to a No. 16 seed, some No. 2s have gone done hard in recent years. In the last five years, four No. 2 seeds have been knocked off in their opening games. The most recent upset came last year when Middle Tennessee beat Michigan State 90-81.

No. 2 seeds Kentucky and Duke play later on Friday.