OMAHA, Neb. — Five days earlier, LSU was licking its wounds as it teetered on the brink of elimination at the College World Series.

Top-ranked Oregon State had just thumped LSU 13-1 to seal up a spot in the winner’s bracket with its 56th win in 60 games. The Tigers would have to beat Florida State just for the opportunity to try and take two games against the team nobody had beaten since late April. And, just for good measure, they would have to do it without one of their best pitchers.

Imagine the emotions then Saturday evening, when the music blared and a hastily scrawled sign reading “Welcome to the Natty” greeted visitors to the LSU locker room. Minutes before, the Tigers cinched up a spot in the CWS championship with a 6-1 win. The difficulty of that accomplishment was not lost on the Tigers.

“We had to beat a good Florida State team for the second time, which was no easy task,” said senior shortstop Kramer Robertson, who went 3 for 3 with a walk and a run scored. “And think about what we did: We just beat a team that had four losses coming into the College World Series and we beat them twice in two days. That’s unbelievable when you think about it.

“We gave them a third of their losses this year. That was one of the best teams I’ve ever seen.”

The blueprint to beating Oregon State, LSU proved, was superb pitching.

“If you pitch well, you’ve got a chance to win,” said LSU coach Paul Mainieri. “It’s that simple.”

On the heels of ace Alex Lange's dominant start in a 3-1 win Friday, sophomore right-hander Caleb Gilbert pitched the game of his life. His career high was 5⅔ innings before Saturday. When he handed the ball to Mainieri to come out of the game, there was one out in the eighth inning.

He allowed only two hits in those 7⅓ innings, one of which was a solo home run that chased him from the game. He struck out seven, five of which were called third strikes.

For the third time in four days, LSU turned the game over to freshman right-hander Zack Hess to record the final outs. While Hess showed some fatigue, he got the job done all the same, sending LSU into the CWS final, a best-of-three series that begins Monday night.

Oregon State was expected to start hard-throwing right-hander Drew Rasmussen on the mound, but shortly before game time announced it would be starting right-hander Bryce Fehmel instead.

“We thought we’d go with (Rasmussen),” Oregon State coach Pat Casey said. “And then we said let’s sleep on that and visit it in the morning. And we changed. We felt it was in our best interest to make sure we had Rasmussen at the end of the game.”

Fehmel spun a gem against LSU in Oregon State’s 13-1 drubbing of the Tigers on Monday, allowing just one run on two hits in eight masterful innings.

But it was a risky decision, considering LSU’s lineup already saw what Fehmel was working with. Perhaps worse, LSU perceived the move like Oregon State trying to pull a fast one.

LSU hitting coach Micah Gibbs said the team spent the morning going over Rasmussen. He caught wind of the change about 45 minutes before first pitch and gathered the lineup to let them know.

“You could tell, the guys’ eyes got big,” Gibbs said. “They were locked in and, to be honest, it got them a little upset, a little fired up, which I thought was great. They took it personal: We’re not going to let this guy beat us twice.”

After the game, Mainieri still wasn’t sure exactly why the change was made, but he thinks he did recognize one thing the change accomplished.

“I think it made our guys very determined to make that move backfire,” Mainieri said.

It did.

Fehmel walked Josh Smith with two outs in the second, then allowed a double to Beau Jordan to bring Michael Papierski to the plate with runners at second and third.

Papierski worked the count to 3-1, got his pitch and did not waste it. The switch-hitter yanked a three-run homer to right field to give LSU a lead it would not relinquish, as Fehmel left the game down 4-0 in the third inning.

Papierski and Jordan punctuated LSU’s day at the plate.

With one out in the fourth, Papierski launched his second home run — this one right-handed — to give LSU a 5-0 lead. Jordan followed with a solo home run off Rasmussen in the sixth.

LSU will face the winner of Saturday night’s game between TCU and Florida in the championship series, starting Monday.

Follow Luke Johnson on Twitter, @ByLukeJohnson.