Top-ranked Gonzaga earned a No. 1 seed in the NCAA tournament, and the Zags will face No. 16 seed Southern in their West Region opener Thursday.

The Zags (31-2) joined Louisville, Indiana and Kansas as top seeds when the 68-team field was announced Sunday.

Gonzaga has been the marker for mid-major success, reaching the NCAA tournament 15 straight seasons and the regional finals four times, including the past two seasons. This season, the Zags, behind Kelly Olynyk, broke through a big barrier on their way to 30 wins and an unbeaten run in the West Coast Conference: the No. 1 ranking.

Southern is going to the NCAA tournament for the eighth time , and first since 2006. The Jaguars (23-9) beat Prairie View 45-44 for the Southwestern Athletic Conference tournament title.