Auburn ace Keegan Thompson hushed LSU’s loud bats.

Thompson pitched a six-hit complete game, and LSU’s offense went cold for a second straight night in a 6-1 loss to Auburn on Saturday night at Alex Box Stadium, setting up a series-deciding rubber match Sunday.

Thompson mowed down a lineup that entered the week ranked second nationally in batting average, allowing, at one point, just two base runners during a six-inning span.

The Tigers (30-6, 9-5 Southeastern) needed a solo homer from Andrew Stevenson in the eighth to avoid their first shutout in nearly two years. Auburn (21-14, 5-9) snapped a seven-game losing streak against LSU and won at Alex Box for the first time since 2011.

The Tigers’ bats were quiet for a second straight night — they had seven hits in a 3-2 win Friday — and their seven-game winning streak ended at the hands of Thompson, a freshman All-American last season.

“That’s as good a pitching performance as I’ve seen in my nine years as the coach at LSU against one of our teams,” coach Paul Mainieri said. “Just in total command. Some nights, you run into a buzz saw.”

Thompson retired 19 of 21 batters during a stretch that began in the first inning and ran through the seventh. He retired the side in three straight innings and a fourth time in the ninth, baffling a group of LSU hitters that swung early. Thompson threw 76 pitches through seven innings and finished with 113 pitches and three strikeouts.

“He was commanding all of his pitches for strikes, but strikes where he wanted them,” shortstop Alex Bregman said. “We just didn’t hit enough balls hard tonight to win.”

LSU has a combined 13 hits in the two games and scored fewer than four runs in consecutive games for the first time this season. The offense couldn’t back up a solid six-hit, seven-strikeout start from Austin Bain, who replaced star freshman Alex Lange.

In a way, it was the Saturday night pitching duel many expected — only with Bain, instead of Lange, on the mound for LSU.

Lange, 6-0 on the year with an SEC-leading 1.39 ERA, was scratched from his start because of what Mainieri termed arm “tightness” — an announcement made after Friday night’s game. The staff is not “overly concerned” with Lange’s arm issue, the coach said, and he compared Lange’s weekend off to what he gave a tired Aaron Nola during his rookie year in 2012.

Bain filled in nicely in a strike-throwing outing that Mainieri called “fantastic,” but LSU’s in a tough spot Sunday with Lange getting a rest. Mainieri hasn’t decided on a starter, but he doesn’t plan for any pitcher to go for more than two or three innings.

Some of the Tigers’ top relievers — Zac Person, Jesse Stallings, Doug Norman and Jake Godfrey — haven’t thrown in the series.

Meanwhile, Thompson hurled a gem in holding LSU to a .188 average.

Mainieri’s team had its best chance against him early. Jake Fraley opened the game with a blooping double over the third baseman’s head, and Bregman had a one-out single. Conner Hale and Kade Scivicque, two of the team’s most consistent hitters, were retired to strand the pair in scoring position.

It was the last time LSU would have two runners on base simultaneously.

Bregman said Thompson was throwing four pitches for strikes: a low-to-mid 90-mph fastball, slider, 12-to-6 curveball and a changeup.

Bain saw it all from the dugout.

“All of his pitches, he was locating very well,” Bain said.

Hale and first baseman Chris Chinea went 0-for-4, and Chris Sciambra, after belting two homers in the midweek, has gone 0-for-8 in two games this weekend. Chinea saw a 13-game hitting streak end.

Auburn leadoff man Anfernee Grier drove in three runs, and AU put away the game with a three-run fifth inning to jump on top 5-0.

“You get into a 2-0 hole against a pitcher like that,” Mainieri said, “you feel like you’re in a 12-0 hole because it seems like such an uphill climb.”

AU scored one in the third and another in the fifth — both on runs driven in by Grier. Grier had an RBI double in the third and an RBI triple in the fifth that bounced past a diving Mark Laird.

“It was a two-man team,” Mainieri said. “Their hitter Grier and pitcher Thompson are both outstanding ballplayers. They carried the team to victory tonight.”

Bain found trouble in the sixth. Daniel Robert, with LSU’s defense shifted hard to the right, led off with an infield single to the left side, and Sam Gillikin followed with a single up the middle. A sacrifice bunt moved the runners before Mainieri pulled Bain for Alden Cartwright.

Cartwright induced a groundout for the second out before allowing a two-run triple — a ball that Stevenson missed on a dive — and an RBI single to make it 5-0.

Bain, a Dutchtown product, impressed in his 5.1 innings.

The rookie was moved into the starting rotation this weekend, replacing Godfrey. Godfrey, who was moved to a midweek role but is available to pitch Sunday. He threw 53 pitches in a Wednesday win over Northwestern State.

Bain’s fastball hovered between 90 and 91 mph, touching 92 at times, and he worked quickly in the biggest start of his career so far.

“Pitching in the SEC is a battle, no matter who you’re facing,” Bain said.

Bain struck out the leadoff batter in the third, fourth and fifth innings. He struck out four of five batters during one stretch, revving up a smaller-than-usual Saturday night crowd at the Box.

He left runners in scoring position in the second, third and fifth, and he got some gems from his defense. LSU turned a double play in the second to end the inning and leave two on base, and Scivicque caught a man stealing in the fourth.

None of it was enough, though — not with Thompson pitching.

“Really outstanding,” Mainieri said. “He’s everything I heard he was. He’s the total package.”

Follow Ross Dellenger on Twitter @DellengerAdv.