The Green Wave opened the season 8-0 after losing 14 of their final 15 games last year.
Timmons scored 19 points in the first half as the Green Wave led 43-22 at halftime. The Jaguars (2-5) stayed close, trailing only 17-16 with 9:43 remaining in the first half. But the Green Wave finished the half on a 26-6 run.
Tulane continued to extend the lead in the second half and pushed it to 31 points, 72-41, on a layup by Lotanna Nwogbo with 6:52 remaining.
Jordan Callahan added 15 points, Josh Davis had 12 and Ricky Tarrant 10 for the Green Wave, who outrebounded Southern 41-29.
Jameel Grace scored 17 points while Quinton Doggett had 12 points and 11 rebounds for the Jaguars, who lost their second straight game by at least 20 points.