LSU improved to 21-13 with the win while Tulane dropped to 18-17. The Tigers will be back in action on Friday when they host Georgia at Alex Box Stadium.
Pettit (W, 4-5) bounced back from a poor outing against Auburn last Saturday with perhaps his most dominant career performance. He retired the first 12 Tulane batters he faced and didn't allow a base runner until Michael Aubrey led off the fifth inning with a walk.
Anthony Giarratano came to the plate next and got the Green Wave's only hit against Pettit. His single was the only ball to get out of the infield against Pettit, but a double play let LSU's starter finish the night without giving up a run.
Clay Harris pitched the next three innings for LSU and allowed two runs, both in the seventh inning on a two-run single from Aubrey.
The Tigers were never threatened until the ninth inning when the Green Wave loaded the bases against reliever Brad David. Gerald Clark cleared them with a double to make the score 9-5, but he was hung up between the bases trying to reach third on the play.
David then got Brian Bormaster to fly out to left to end the game.
The six pitchers who took the mound for Tulane could not contain the LSU's bats. Shortstop Aaron Hill led LSU with the first its four round trippers and four RBI. His two-run shot to left field in the third inning made the score 3-0, coming after an RBI double from Sean Barker in the first.
Hill drove in his next two runs in the fourth on a single that ended the night for Tulane starter Kris Kline (L, 1-2). Ricky Fairchild replaced him and was pelted in the fifth inning with home runs from Barker, Jason Columbus and Chris Phillips, giving LSU an 8-0 lead.
LSU scored an insurance run in the ninth on an RBI single from Phillips.