Paul Mainieri leaned against the dugout railing, resting his face in his hand. LSU had loaded the bases in the fifth inning on Thursday night, but Mainieri frowned. The Tigers trailed by double digits.

LSU had lost games this season, but never like this. Never 16-9, using every healthy player on the bench by the fifth inning, down by 10 runs when they went to bat for the last time.

The No. 15 Tigers dropped their fourth straight game, beginning the series against No. 25 Florida with a definitive loss. They gave up more than 10 runs for the third time in six games.

LSU (24-15, 9-7 Southeastern Conference) did not have pitcher Zack Hess to open a weekend series for the first time this season. Hess pulled a muscle in his groin his last start. His health had improved in the days before the game, but coach Paul Mainieri said he did not have the endurance to give LSU a full start. He could have pitched an inning or two.

“If Zack Hess had started tonight and he was healthy,” Mainieri said, “I'm pretty confident we wouldn't see that kind of a baseball game.”

After practice on Wednesday, sophomore Ma’Khail Hilliard found out he would start an SEC game for the first time since last May. LSU thought he could throw “four or five good innings,” Mainieri said.

Instead, the Gators (26-14, 7-9) batted around in the second inning to score six runs. Hilliard, who gave up seven hits, lasted two innings as Florida jumped on his fastball and avoided his curveball. He took the loss.

“He wasn't fooling them at all,” Mainieri said.

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Florida had 10 hits by the end of the third inning. Then Chase Costello gave up a three-run home run. So did Clay Moffitt — the first earned runs he allowed this season. The Gators tacked on seven more runs by the fifth inning. LSU put in the last of its backups.

Losing 13-0, senior outfielder Antoine Duplantis said the offense had to change its strategy. The hitters could not steal or try hit-and-runs.

“You have to swing your way back into the game,” Duplantis said.

The Tigers loaded the bases in the fifth inning, and freshman Cade Beloso singled, driving in two runs. The Tigers ended up recording 16 hits. Saul Garza even hit his first home run. They scored seven runs over the final three innings.

But Florida hit four home runs — its last a solo shot in the ninth inning — and recorded 20 hits, extending its lead through its final at-bat.

As Hess watched from the dugout, LSU lost for the fifth time in its last six games.

“We're trying to learn from our mistakes,” Duplantis said. “This is only one loss. It's a new weekend. If we win tomorrow, we're back where we want to be, right in the mix of things.”

Follow Wilson Alexander on Twitter, @whalexander_.