No. 1 Gonzaga 64, Southern 58: Kelly Olynyk scored 17 of his 21 points in the second half and grabbed 10 rebounds as the Bulldogs staved off an upset bid by the Jaguars in the second round of the NCAA Tournament in Salt Lake City.

Kevin Pangos scored 16 points and Gary Bell Jr. added 11 for top-seeded Gonzaga (32-2), which faces Wichita State on Saturday in the West Regional for a berth in the Sweet 16.

Derick Beltran scored 21 points and made four 3-pointers to pace Southern (23-10), which was attempting to become the first No. 16 seed to win an NCAA tournament game. The Jaguars were tied at 56 after Beltran’s 3-pointer with 3:46 to go before a 3-pointer by Bell 27 seconds later put Gonzaga ahead to stay.

Beltran hit two free throws with 2:28 remaining but Southern didn’t score again. Pangos drained a 3-pointer with 1:55 left to make it a four-point game and later added two free throws with 16.3 seconds to go.

Gonzaga led 34-31 at halftime and appeared to be in control when Olynyk’s basket provided a 52-41 lead with 9:36 to play. Southern answered with a 13-2 spurt to tie the game at 54 on two free throws by Brandon Moore with 4:08 remaining.

GAME NOTEBOOK: The six-point margin was the closest in a No. 1 versus 16 matchup since Murray State fell 75-71 to Michigan State in 1990. … Pangos had four of the Bulldogs’ eight 3-pointers. … Gonzaga had a 40-27 rebounding advantage, collecting 11 offensive boards to Southern’s three.