Tennessean photo by KAREN KRAFT -- Vanderbilt's Xaiver Turner slides into second but gets called out after a tag by LSU's Alex Bregman during the third inning of Friday night's game at Hawkins Stadium in Nashville, Tenn.

NASHVILLE, Tenn. — LSU’s relievers and hitters didn’t look so bad during the first month of the season.

Vanderbilt made sure that changed.

The Commodores swept a doubleheader Saturday to win the three-game Southeastern Conference series, exposing the Tigers’ relief pitching and stifling their hitters in 5-3 and 9-3 wins at Hawkins Field.

LSU (17-4, 1-2) had just nine hits in Saturday’s pair of games, and Vanderbilt (18-3, 2-1) scored seven runs off relievers to shake off a series-opening loss Friday.

“Obviously,” LSU coach Paul Mainieri said, “a long, tough day for us.”

LSU starting pitchers Jared Poché and Kyle Bouman, both making their SEC debuts, allowed nine hits and seven runs and walked seven while striking out just four.

The starting pitching’s struggles, though, paled in comparison to the hitting and a collapse by the bullpen in Game 2.

The teams played a twin bill Saturday because of the high likelihood of rain Sunday. The day started at 2:15 p.m. and didn’t end until 8:36 — six hours LSU would like to forget, especially the rubber match.

An opponent scored nine runs or more for just the third time in the past 144 games, a span dating to early in the 2012 season.

In the late game, LSU trailed 4-2 entering the sixth. It was a nightmarish inning for a pair of LSU relievers.

Vanderbilt batted 11 in the inning and scored four runs. Kurt McCune and Cody Glenn combined to allow four hits, walk two and hit one.

McCune walked the leadoff batter in the sixth, a guy hitting .188.

“Opened the floodgates,” Mainieri said of the walk.

McCune allowed four straight hits, including a double, and three runs scored before Glenn replaced him.

Glenn hit his first batter on a full count to load the bases. He walked the second on four pitches to score a run.

“Cody, once again, when he elevates the ball, he gets in trouble,” Mainieri said. “We can pitch a lot better than we did today, certainly. We’ll need to. We have to find somebody who can win a game besides Aaron Nola on the weekend — that’s for sure.”

Mainieri pulled Poché after facing the first batter in the fifth. The Commodores got five hits off the freshman from Lutcher. He walked five batters, one intentionally, and struck out three.

In the first game of the DH, Bouman, a junior college transfer, allowed three runs in a 41-pitch first inning.

“I’m sure coming into the hostile atmosphere, it’s a little bit different,” LSU center fielders Andrew Stevenson. “Got hit around early, but they settled down.”

In the rubber match, LSU had a chance in the top of the sixth to cut into a two-run deficit.

Conner Hale led off the inning with a single and then moved to second on a passed ball. A fly out advanced him to third with one out.

He never moved. Christian Ibarra struck out, and Andrew Stevenson grounded out to the pitcher.

It was a common theme during the three-game series.

Outside of Sean McMullen, LSU had zero extra-base hits over the three-game series against a hard-throwing pitching staff Mainieri calls the best in the nation.

“They ran a pitching staff out there that some major league teams would like to have, quite frankly,” he said. “

Against that staff, LSU’s hitters flopped.

Shortstop Alex Bregman went hitless in Saturday’s two games and had an 11-game hitting streak end. Stevenson had a 17-game hitting streak end in the nightcap.

LSU had just five hits in the rubber match and four in the first game. The Tigers had five in a comeback 4-2 win Friday night.

“We know that it’s behind us. We’ve got to move on,” McMullen said. “There’s no point to look back at it or to dwell on it. We have 27 games left in this league. We’re not going to hang our head. We know what we’re capable of.”

In Saturday’s early game, the Tigers bats were muted against Vandy starter Jared Miller, and the Dores got two runs and four hits off relievers Nate Fury and Henri Faucheux.

“We ran into some really good pitching,” said Stevenson. “Kept us off-balance. We weren’t used to seeing that. We’ll come out and get them next time.”