SALT LAKE CITY (AP) - It was every frontrunner's nightmare. Top-seeded Gonzaga ran into a No. 16 seed that wasn't playing like one, a crowd itching for an upset and the very real prospect of making history in a most embarrassing way. Somehow, the Zags maneuvered their way out of that mess Thursday with a 64-58 win over Southern University, but not before they provided plenty of fodder for all those who wondered if that small school from the small conference really belonged at the top of the West Region bracket. "The more I watched film on them, the more I thought, 'This could be a real grinder,'" coach Mark Few said of the Jaguars, champions of the Southwestern Athletic Conference. They don't give you many easy opportunities. They're very patient on offense. Gonzaga's win wasn't safely in hand until the final buzzer sounded. 1 seeds improved to 113-0 since the NCAA tournament field was expanded to 64 teams in 1985. Led by Derick Beltran's 21 points, Southern (23-10) made life hard on the West Coast Conference champions from beginning to end, blocking eight shots, making 10 3-pointers, harassing its star player, Kelly Olynyk, and never letting the Bulldogs out of striking range. Olynyk scored 17 of his 21 points in the second half to help the Zags (32-2) advance to Saturday's game against Wichita State. But there was no celebration. Just a big sigh of relief. "That crowd gets going, everyone wants to see that first 1-16 loss," Few said. My guys deserve credit. They showed a lot of poise down the stretch when things weren't going their way. And the Jaguars, the team from the school in Baton Rouge, La., with enrollment 6,900, never stopped scrapping. This was a program nearly wiped off the map three years ago because of an NCAA investigation into problems in the classroom. They still have players on the roster who were around for the 20-plus-loss seasons that ensued. Their coach, Roman Banks, looked to Gonzaga - tiny school with big dreams - as the program his players should try to emulate. "We were basically an unknown ballclub that showed they can play the game of basketball," Banks said. But we came here to win a ballgame, not play a ballgame. Though Olynyk was the force that kept Gonzaga ahead through the second half, it was a pair of 3-pointers - one by Gary Bell Jr., the next by Kevin Pangos - that gave the Bulldogs their small cushion after Southern tied things at 56 with 3:45 left. Bell's 3 made it 59-56 after Beltran hit a 14-footer on the baseline to close out a 15-4 Southern run and tie the game. Beltran answered with two free throws to cut the deficit to one, but Gonzaga responded by working the ball to Pangos, whose 3 made it a four-point game. Yondarius Johnson and Malcom Miller both had open looks on the next possession for Southern but neither could convert. The Jaguars did almost everything right in this game, but missed five open shots down the stretch that could have put them over the top. "From a coaching perspective, you learn that two or three bad possessions can cost you a ballgame," Banks said. Pangos (16 points) made two free throws with 14.3 seconds left to seal the game. Only then did the Gonzaga cheering section rile up and the rest of the crowd, pulling for the underdog, settle down. "Everyone was so moved by their effort, their resilience, their confidence," Few said. If I wasn't coaching on the other sideline, they'd be a tough team not to root for. This Jaguars will go down among the teams that produced the closest calls in the history of 1 vs. 16 matchups, next to the 1989 Princeton squad that barely lost to Georgetown and the East Tennessee State team that lost to Oklahoma by one in the opening round of the same tournament. This game provided a fitting start to March Madness 2013 - the closing act to a season filled with upsets, shifts atop The Associated Press poll and no dominant team. Gonzaga's critics felt the Zags got to No. 1 by default more than anything. The Zags shut out that talk and said they'd take their first game as NCAA tournament front-runners the way they'd taken the previous 33. The Jaguars fell behind 7-0 over the first 3½ minutes, but reeled off eight straight points after that. For the rest of the afternoon, this looked nothing like a typical 1-16 matchup. Southern took away the high-low game between Olynyk and forward Elias Harris, frustrated the Zags relentlessly and, during one stretch early in the second half, blocked three of Gonzaga's inside shots in the span of 48 seconds. Despite its struggles, Gonzaga kept working the ball to Olynyk in the second half. At one point, he had 17 of Gonzaga's 20 second-half points. "We started calling his number, directing the ball his way a little bit and guys figure out where we're having success," Few said. Tonight, it was with 'KO.' At the end, what the Bulldogs really needed was another option. Not until then did Bell and Pangos come through. "Any win in the tournament is a good win," Olynyk said. We have to kind of take that into consideration and move forward. .