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Former LSU Tiger and current analyst Kelvin Sheppard, left, speaks with LSU defensive coordinator Bo Pelini as they walk off the field following the Tigers' home opener against Mississippi State during the coronavirus pandemic, Saturday, September 26, 2020, in Baton Rouge, La. Mississippi State won 44-34.

Ed Orgeron was in his personal locker room inside Tiger Stadium when the LSU coach heard someone at the door.

It was Bo Pelini. The defensive coordinator's first game in his return to the program couldn't hardly have gone worse. His tight man-to-man coverage game plan, built around limited personnel, was torched by Mississippi State's Air Raid attack in a 44-34 loss.

Defensive backs took wrong paths with crossing routes or couldn't keep up. Wheel routes went uncovered. Cornerbacks were beat one-on-one at the line of scrimmage.

Bulldogs quarterback K.J. Costello's 623 passing yards set a single-game Southeastern Conference record. It was the most passing yards ever surrendered by an LSU defense, and 383 of those yards came after the catch.

Orgeron told reporters Monday that Pelini was the first person to visit him after the game.

"Coach," Pelini said, "I should've done better."

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The 52-year-old Ohio native is known for wearing his fiery emotions on his sleeve. Pelini gave a passionate pre-game speech Friday night, Orgeron said, and he had the defense motivated. But after a gutting loss that took nearly four hours to complete, Pelini was quietly reflective.

Not apologetic, Orgeron said. Not humble. Just hurt.

"He was hurt just like everybody else," Orgeron said. "... Hurt that he didn't do better. Hurt that the defense didn't do better. Just like we all are."

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Over the next 24 hours, Pelini reviewed a game plan that flopped on national television, in front of thousands of Tigers fans who eagerly anticipated his return, who suddenly had grounds to question the direction of a defense that helped win a national title in 2019.

A common question formed in the public: Why didn't LSU eventually back off in coverage? 

Mississippi State coach Mike Leach had his own questions.

Starkville's first-year coach said his staff prepared for an LSU secondary that wouldn't play so tightly in man coverage. Leach said he thought LSU's corners and safeties would back off a bit, give themselves some room to cover an offense that would be throwing the ball almost 80% of the time.

"We thought they'd play looser," said Leach, whose Bulldogs (1-0) are now ranked No. 16. "It turned out that they didn't play so loose and the space was getting crowded more and more, so we felt like we ought to go over the top."

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When asked Monday what prevented in-game adjustments, Orgeron didn't delve deeply into details.

He said "all those are Bo's decisions" and "we talked about it." There were some adjustments they could have done, he said. Not necessarily play zone defense, but perhaps different variations of man coverage where defenders hand off receivers.

Indications seem that there was a firm game plan to play tight coverage, and, even when things started to go wrong, Pelini believed that a young and inexperienced group of defensive backs would eventually catch on.

"We thought we could man up with their receivers," Orgeron said. "We should have made a couple more adjustments during the game."

Will No. 20 LSU (0-1) make those adjustments for their Saturday game at Vanderbilt (0-1) — another spread offense team that played No. 13 Texas A&M close?

They may, Orgeron said. They may not.

"Depends," he said.

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It depends on how soon All-American cornerback Derek Stingley will be game ready. The star sophomore missed Saturday's game after spending the previous night in a hospital because of an "acute" illness unrelated to COVID-19, a school news release said.

Orgeron said Stingley still wasn't medically cleared as of Monday morning, although he said Stingley could return to practice as soon as Tuesday.

Not having Stingley was likely the most crucial, if not deciding, factor in LSU's loss on Saturday. The 6-foot-1, 195-pound Baton Rouge native thrives in one-on-one coverage, and LSU started two cornerbacks who had never played a college football game in the SEC before.

Darren Evans, a graduate transfer from Nicholls State, started in place of Stingley and rotated out of the game after early struggles. Costello also attacked true freshman Eli Ricks, a five-star who enrolled in the spring, frequently.

The rotation wasn't much deeper or experienced.

Cordale Flott, an experienced sophomore, sometimes rotated to cornerback but he was needed as the team's nickel safety — a position that opened when starter Kary Vincent opted out during preseason camp.

Sophomore Jay Ward, who saw minimal playing time in 2019, usually filled in at corner; but Orgeron said he missed practice for two weeks.

"We didn't even know he could play," Orgeron said. "He played a lot of snaps. Thought the did a fairly good job, but obviously was a little rusty there."

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The poor defensive performance surprised Orgeron. He had praised the defense during preseason camp, saying it was a better unit than it was at any time last season. It was consistently winning against LSU's offense in practice, Orgeron said, and it was constantly pressuring the quarterback.

The Tigers pass rush produced five sacks Saturday, but those pass rush numbers are shrouded by the big, bold number 623 — an amount of passing yards LSU's defense took three games to surrender at the start of last season.

Orgeron said the defense returned to fundamentals Monday. They practiced stance, alignment and assignments.

"We've got to work on our coverage," he said.

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Email Brooks Kubena at bkubena@theadvocate.com.