Auburn forward Jordon Granger was ejected from Friday's SEC quarterfinal after throwing a punch at LSU's Jordan Mickey.
Granger, the team's second-leading rebounder, finished with eight points and five rebounds.
Auburn sent the game to overtime when KT Harrell hit a game-tying three-pointer at the buzzer. Harrell then scored five points in overtime to lift Auburn over LSU, 73-70.
Harrell finished with a game-high 29 points, while Keith Hornsby led LSU with 24.
Auburn will now face No. 1 seed Kentucky in the SEC semifinals on Saturday.
- Dan Gartland