Southern Miss outscored the two-time defending champion Blue Raiders 10-7 in the extra period, and will face No. 4 seed Marshall (22-10) in a Friday semifinal game. The Golden Eagles have won two conference tournament games for the first time since 2010.
Edwards made a 3-pointer and Dominic Magee added another 3 and two free throws, and Southern Miss led 70-66 with 1:44 remaining. Nick King's layup pulled Middle Tennessee to 70-68, but Kevin Holland blocked King's next shot and Giddy Potts missed a jumper with 13 seconds left.
Potts, who was 4 of 4 from long range, hit a 3-pointer with 18 seconds left in regulation to force overtime.
Edwards made a career-best 5 of 6 from beyond the arc. He scored a career-high 29 points against Florida International in Wednesday's first round game, and scored 21 against Louisiana Tech in the regular-season finale.
Magee finished with 12 points, nine rebounds and three steals. Tyree Griffin added 11 points and six assists for the Golden Eagles.
King scored 17 points and grabbed nine rebounds, and Potts had 14 points for Middle Tennessee (24-7).
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