9th-seeded UAB, who blew past Charlotte in the first round, continued their tournament run by upsetting Marquette.
UAB used their tough man to man defense to force Marquette into 30 turnovers, which set a new C-USA tournament record.
Morris Finley led the Blazers with 23 points, including hitting 10 of 10 from the free throw line. Eric Bush added 17 and Demario Eddins tossed in 16 in the win.
"We had nothing to lose coming into this game," said UAB head coach Mike Anderson. "It was an unbelievable effort by our whole basketball team. With the exception of a few other people and the players in our locker room, I think those are the only people who believed we could pull this off. I think you saw the end result. They believed, that's what I'm talking about, they had no fear."
"None of us are shocked," added guard Eric Bush. "We knew we could compete with them. We knew they were a very good team coming in, but it's really hard for them to play that many minutes against the way we played. I think it was a matter of wear and tear towards the end of the game that we prevailed."
Marquette had four players score in double figures, led by guard Travis Diener's 19.
Saint Louis 69 Southern Miss 56
After trailing by 15 at the half, Southern Miss rallied to pull within 48-46 with 7:24 remaining in the game. However, Saint Louis then began to pull away and eventually won by 14.
The Golden Eagles couldn't overcome the hot-shooting Billikens, who shot 58% from the field, including connecting on 7 of 11 three-point attempts.
Anthony Drejaj came off the bench to pace Saint Louis with 27 points on 10 of 11 shooting from the field. All-Conference guard Marque Perry added 15 points and 6 rebounds.
"I think Saing Louis is a very good basketball team," said Southern Miss head coach James Greene following the loss. "You have to give them credit for coming out and defending us so well. When you put them together as a team, I think they play as good as anyone we played all season."
Southern Miss, who finishes the season 13-16, was led by Charles Gaines 19 points and 9 rebounds.