OMAHA, Neb. — Paul Mainieri said LSU didn’t “choke” in its 0-for-2 stay at the College World Series in 2013.

His team coughed it up Sunday.

Starting pitcher Jared Poché unraveled after a two-error inning, and the Tigers defense joined their sluggish offense in a stunning 10-3 loss to TCU, a gruesome opening act for the nation’s top-ranked team.

In its worst loss of the year, LSU (53-11) tied a season high with four errors and did it for the first time in the past 60 games. Third baseman Conner Hale had his first error in 21 games; Poché committed an error for the first time in 16 starts; and even All-America catcher Kade Scivicque had an error — his first in 18 games.

“It was just a total collapse for us on a big stage,” Mainieri said. “We picked kind of a rough time to not play our best baseball.”

They were bumbling and stumbling on the grandest stage in the college game.

It was a shocking development for a squad that won the Southeastern Conference regular-season title, rolled through the first two rounds of the NCAA postseason without a loss and hadn’t left the top spot in the polls since April.

Poché (9-2) allowed six runs in 4.1 innings and committed back-to-back costly errors in the fourth on comebackers. Just three of his six runs were earned, but two of those unearned runs scored because of his own gaffes.

The sophomore from Lutcher retired his first nine batters but fell apart following those errors in the fourth.

“I think that was a big part of the game. Momentum definitely shifted their way,” Poché said. “It’s my fault.”

Said Mainieri: “I’m in a little bit of a state of shock. It went downhill so quickly.”

TCU starter Preston Morrison (12-3) stymied one of the nation’s most potent lineups, allowing five hits in his seven innings and retiring the final 12 batters he faced.

The Tigers stranded two runners on third base in the first four innings and had a runner thrown out at the plate in the third.

They fell into a 10-1 hole — by far their largest deficit of the season — before Jared Foster’s solo home run and Scivicque’s two-out run-scoring single in the eighth off reliever Brian Howard.

Mainieri’s club now has a steep hill to climb in this double-elimination event. The NCAA tournament’s No. 2 seed, LSU will play the Vanderbilt-Cal State Fullerton loser — those teams began play Sunday night, but the game was suspended by stormy weather until 11 a.m. Monday, with Fullerton leading 3-0 in the sixth inning — at 2 p.m. Tuesday in an elimination game. The Tigers must win four straight elimination games — on Tuesday, Thursday, Friday and Saturday — to advance to the best-of-three national championship series.

They first have to win Tuesday to avoid a second straight two-game stay in Omaha after LSU went 0-2 in 2013. Just two teams since 1999 have lost their first game at the College World Series and gone on to win the national title.

Freshman ace Alex Lange (11-0, 1.89 ERA) is scheduled to start Tuesday. The Tigers are 14-2 in games he starts this season.

“I think our guys will feel confident knowing we’ve got an All-American pitching for us,” Mainieri said.

They’ll be looking to flush this one quickly.

Players talked of moving on immediately afterward from a somber postgame locker room. Many scrolled through their phones while sitting in their lockers, awaiting some 15 to 20 media members to parade through their area.

It was a gloomy scene for a squad that rolled into TD Ameritrade Park with the highest confidence.

This park hasn’t been friendly to the Tigers. LSU has been outscored 16-6 and is 0-3 in two trips to the CWS since the expansive venue opened in 2011. Sunday’s three-run output was the highest total for the Tigers in those three games.

They got one of those runs off Morrison, a former Team USA hurler who struck out five and didn’t walk a batter.

“He was pounding the (strike) zone, mixing in all three pitches,” first baseman Chris Chinea said. “He’s a good pitcher, been proven in his league for a while. We didn’t come through in certain at-bats.”

The offensive woes began early. The Tigers stranded Andrew Stevenson at third base in the second and left Scivicque at third in the fourth. Chinea ended both innings by being retired. Foster was thrown out at the plate to end the third inning while running from second base.

Poché had his fallout the next inning. He threw 5 feet over Chinea’s head at first — a three-base leadoff error that allowed TCU’s Cody Jones to reach third. He fired another comebacker high and wide of first during the very next at-bat — another error that left men on the corners.

And then what happened?

“I was definitely commanding my pitches, then I lost command,” he said.

The Horned Frogs (50-13) took him for four singles and three runs, and Poché walked two over the next 10 batters he faced.

“I’ve seen this happen before with baseball players,” Mainieri said. “It’s amazing a kid can pitch so well, but then he has to make a throw like that. It’s probably more psychological than anything else. It changed the complexion of the game.”

Mainieri pulled Poché for reliever Hunter Newman. The Tigers used seven relief pitchers the rest of the way, patching together the game so as not to burn any one reliever.

They didn’t, Mainieri said, as everyone remains available. What they did do?

“We didn’t play our best game,” Foster said. “Kind of picked a bad time to do it.”

Follow Ross Dellenger on Twitter: @DellengerAdv.