Pettit (7-1) started poorly but eventually found his groove and finished with eight strikeouts to go with six hits, six earned runs and three walks.
"I've had a lot of practice (rebounding)," said Pettit. "I've had a few games where I've had to do that. It's frustrating when you give up runs like that.
Luckily, these guys picked me up. They showed that no matter how much we're down, we're still in the game."
A huge fifth inning allowed the Tigers to claim the lead. With two outs, Jon Zeringue hit shot to the gap at shortstop, and a fielding error by Vols' shortstop Brian Cleveland allowed him to reach first. Quinn Stewart came up next and blasted a deep fly ball to the right field warning track. Tennessee's Michael Rivera made the catch but collided with outfield wall and lost the ball in the process. Stewart ended up with a triple that scored Zeringue and Clay Harris, giving LSU a 7-6 lead.
Matt Liuzza brought in another run with a double to right field, and Bruce Sprowl followed him with an RBI single up the middle.
Ryan Patterson brought in the final run with another RBI single.
The Volunteers got a quick jump on LSU in the first inning with an RBI single by Nick Crowe. Three more runs came later on a particularly strange play, a rare inside-the-park homerun by Javi Herrera.
The hit went right down the right-field line into the corner of the outfield, where it got wedged under the rolled-up tarp that is used to cover the field. Right-fielder Jon Zeringue threw up his hands to indicate the ball was out of play, but first base umpire Fred Cannon refused to acknowledge the signal, and Herrera raced around all three bases, bringing in 3 runs in the process and giving Tennessee a 4-0 lead.
LSU chipped into the lead with a solo homerun by Patterson in the bottom of the first.
Pettit continued to struggle though, and Tennessee added two more runs in the third with a two-run homer by Kyle Norrid.
A two-RBI single by Blake Gill in the third cut Tennessee's lead to 6-3. Two more runs came in the fourth, off sacrifice hits by Liuzza and Sprowl.
It was a tough win for Smoke Laval's Tigers, who remain in first place in the Souteastern Conference with a one and a half game lead over Auburn.
"Mentally we stayed in the ballgame," said Laval, "which is tough to do because you're down 6-1. They're having fun and you're not."
Tigers take Tennessee series
Tiger Blitz Top Stories
LSU Football Defensive Bye Week GradebookLSU's defense has been the Tigers' rock this season under Dave Aranda, but did their grades all come out perfect in Tiger Blitz' Bye Week Gradebook?
Tiger BlitzYesterday at 9:08 AM
Five Questions LSU must answer stillThe Tigers certainly have already answered a lot of questions this team had following the Auburn loss, but there’s still some questions that the Tigers have to answer to achieve…
Tiger BlitzYesterday at 1:00 AM
LSU Football Offensive Bye Week GradebookTiger Blitz hands out grades for the first half of the season for the LSU Tigers on offense as they enjoy their bye week.
Tiger BlitzWednesday at 6:45 AM
LSU OL commit honored to be a TigerTiger Blitz was in DeSoto, Tex. to check in on 2017 LSU offensive line commit Ed Ingram and to get his thoughts on his senior season and LSU's impressive run.
Tiger BlitzWednesday at 3:55 AM
New Tiger Blitz members receive a great perk!Another great partnership from the folks at Scout.com brings a big benefit to new Tiger Blitz/Scout members!