The Tigers (33-19, 12-15 SEC) lost a series for the first time in three tries but remained in eighth place in the overall league standings. Mississippi State and Tennessee lost its games on Sunday and are tied for ninth place with 11-15 records.
Vanderbilt (30-22, 14-13) improved its chances for a spot in the eight-team SEC Tournament with its first series victory in Baton Rouge since 2002. The Commodores are tied for sixth with South Carolina heading into their final regular season series.
LSU travels to Metairie, La. to face top-ranked Rice in the Wally Pontiff Jr. Classic at 7 p.m. Tuesday before closing its regular season slate at Florida next weekend. Senior right-hander Chris Cahill (1-0, 1.74) will start against the Owls Tuesday, marking his first starting assignment since a 7-2 victory over UNO on April 26.
Shortstop Ryan Flaherty and pinch hitter Kurt Lipton provided pivotal solo homers for Vanderbilt on Sunday, as the Commodores finished the series with seven total dingers. Vanderbilt entered the weekend with only 10 homers in SEC play.
Rhoden (3-0) was credited with the win in 1.1 innings of relief of starter Ty Davis. Christiani was equally impressive, holding the Tigers to one hit in the final three innings to pick up the save.
LSU held a 1-0 lead through two frames thanks to J.T. Wise's solo homer in the first, but the Commodores countered with three in the third inning.
Starter Daniel Forrer walked third baseman Brad French to lead off the third. Two outs later, the southpaw's outing was finished after issuing three consecutive RBI singles to Flaherty, Hernandez and Robin, giving Vanderbilt a 3-1 lead.
"We had our chances, but we can't be walking lead-off hitters early," said Laval. "Then you have to rely on the bullpen, which is thin right now due to injuries."
For Waguespack it was his second blast of the season and his first since March 3 against Houston.
The Commodores added single runs in the sixth, seventh and eighth innings, including solo homers by Flaherty and pinch hitter Kurt Lipton.
Christiani retired nine of the 12 batters he faced and never let the Tigers mount another comeback.
"When you get a team that pitches really well, it is very difficult to bunch hits together," said Laval. "I think we only got two hits in one inning once in 27 innings."
Ramirez (2-1) suffered the loss, allowing two runs on one hit, while walking two in 1.1 innings of relief.