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From left, LSU pitcher Collin Strall (30), LSU starting pitcher Eric Walker (10), LSU first baseman Chris Reid (17), and LSU pitcher Austin Bain (18) in the dugout after Walker was pulled in the third inning during Game 6 of the College World Series between LSU and Oregon State, Monday, June 19, 2017, at TD Ameritrade Park in Omaha, Neb.

Advocate staff photo by HILARY SCHEINUK

OMAHA, Neb. — When playing against a team with four losses in 59 tries, every mistake and unfortunate circumstance is compounded, each successive crack hastening the arrival of the overwhelming avalanche.

There were almost too many mistakes and misfortunes to count in LSU’s 13-1 loss to Oregon State on Monday night. LSU walked 12 batters. Eric Walker, who had been an absolute stud for LSU in the postseason, left the game with forearm tightness in the third inning.

At the plate, LSU only had one hit through six innings. On the base paths, LSU was hurt by its own poor choices and by a missed call on the umpires. It seemed all Oregon State needed was for LSU to not have a crisp day in the field, but the Tigers were at times sloppy.

“It wasn't what we expected or hoped for, obviously,” said LSU coach Paul Mainieri said. “A heck of a way for a 17-game winning streak to end.”

Oregon State took advantage of so many things to snap an LSU win streak that had been going since May 11. But the logical place to start, where things truly unraveled, is the top of the sixth inning, when the Tigers’ litany of mistakes amounted to them handing the dagger over to the Beavers.

A leadoff walk led to a pitching change and two more walks, loading the bases with one out for PAC 12 Player of the Year Nick Madrigal.

Even then, at this point, LSU found itself in a manageable 3-0 deficit — a daunting hill to climb, to be sure, against a team that had not blown a two-run lead all season. But then, LSU would have had to limit the mistakes to three walks in the inning and leave the bases loaded.

Madrigal tapped the ball back to freshman Todd Peterson, a play that should have at least resulted in a runner being thrown out at the plate. Instead, Peterson could not field the ball cleanly and his only play was at first base.

Another pitching change — LSU called for dependable senior right-hander Hunter Newman with runners at second and third, looking to keep the deficit to a still manageable four runs with four innings of offensive baseball to go.

“We went to Hunter Newman early to keep us in the game,” Mainieri said.

Newman’s first four pitches were balls, sending Trevor Larnach to first base to load the bases. His fifth pitch was deposited into the left field bleachers at TD Ameritrade Park by KJ Harrison, a grand slam that gave the Beavers an 8-0 lead and officially put the game into out-of-reach territory.

Perhaps the game would have unfolded differently had LSU not received its first major blow in the top half of the third inning. Walker, after his fourth pitch of the inning, backed away from the mound and looked into the LSU dugout.

The freshman who had been so good in the postseason left the game with tightness in his forearm, forcing LSU to make the first of what would be seven pitching changes.

“When Eric Walker went out, it just put us behind the eight ball there, and we weren't very competitive tonight,” Mainieri said.

And while Caleb Gilbert kept the game stable for two innings after Walker’s exit, he could not overcome the miscues of his teammates and the battling spirit of the OSU lineup.

The Beavers worked Gilbert for 70 pitches in just 2.2 innings, not allowing him to truly work a long relief outing. It was a concerted effort from Oregon State after Gilbert struck out four of the first six batters he faced.

“We just tried to get him in pitch counts because we really weren’t doing a lot with him,” OSU coach Pat Casey said.

They got some help from LSU. A Kramer Robertson error in the top of the fifth allowed Nick Madrigal to come to the plate with two outs, and Madrigal singled into center field on a hit and run. LSU’s Zach Watson missed the cutoff man with his throw, allowing Madrigal to take second base.

Larnach followed with a two-out, two-strike, two-run single. Gilbert, who had been pitching well, exited the game one batter later, exposing the weak spot of LSU’s roster — its middle relief — to the best team in the country.

Offensively, LSU managed just two hits in eight innings against Oregon State starter Bryce Fehmel, who induced lazy fly ball after lazy fly ball by keeping the Tigers off balance with a three-pitch mix.

“I did that for eight innings to the best of my ability, and it worked out,” Fehmel said.

Zach Watson provided LSU’s lone run with a solo homer in the seventh inning. That home run, his ninth this season, made it an 11-1 game.

LSU will face Florida State in an elimination game Wednesday at 6 p.m. Jared Poché, who earned a win in relief against Florida State in LSU’s CWS opener, will start the game.

“We’ve got a lot to play for, and we’ll just take it one at a time,” Mainieri said. “Hopefully we can get another shot at Oregon State later in the week.’

Follow Luke Johnson on Twitter, @ByLukeJohnson.