AUBURN, Ala. — Auburn entered Saturday’s NCAA regional matchup with Clemson unbeaten at Plainsman Park this year in 16 tries against left-handed starters.

It left with a 5-2 loss on its ledger, courtesy of Clemson starter Casey Harman.

Harman threw his first career complete game, holding top-seeded Auburn (41-20) to a season-low five hits and putting the Tigers in the unenviable position of needing to win three straight games to make it out of the regional.

“Harman was outstanding,” Auburn coach John Pawlowski said. “And I think against good pitchers you need to have quality at bats. And we just didn’t have enough of them today.”

Auburn will play third-seeded Southern Miss today at 2 p.m. ET in an elimination game. The winner faces Clemson at 7 p.m.

Because second-seeded Clemson (40-21) has not lost, whoever emerges from the losers bracket must beat the Tigers twice. An if necessary game would take place Monday at 7 p.m.

“It’s tough to play out of the losers bracket, but it’s not impossible,” Auburn first baseman Hunter Morris said. “So we’ve got to come out and our focus has to be out there 100 percent from pitch one against Southern Miss.”

Said Pawlowski: “We have to have a short memory.”

Auburn, which led the SEC in nearly every offensive category, never solved Harman (7-2), the Clemson ace who sported a 4.14 ERA during the regular season. Auburn had only been held to five hits one other time this year, a 7-1 loss against Alabama’s Jimmy Nelson in the SEC tournament last week.

Since clinching the SEC West with a sweep of Ole Miss two weeks ago, Auburn has hit .233 and scored 22 runs in five games.

“Our offensive approach has not changed,” Morris said. “Some guys have had some good outings, but it’s our job to keep bouncing back and find a way to score runs.”

Clemson had no such offensive problems. The Tigers scored five runs off Auburn starter Grant Dayton (8-3) in the first four innings.

Mike Freeman sparked a three-run first with a two-run homer to right. Clemson added two more in the fourth to make it 5-0, getting back-to-back doubles from Richie Shaffer and Wilson Boyd for one run and scoring another on a throwing error by third baseman Dan Gamache.

But Dayton settled down from there, retiring 12 straight at one point. He finished with nine strikeouts, going 7 2/3 innings before coming out of the game after a career-high 130 pitches.

“I just didn’t have it the first inning,” Dayton said. “I made a couple mistakes and it showed on the scoreboard. But after that I settled in and was able to get my fastball where I wanted it.”

Harman was every bit better, however. He didn’t allow a hit through four innings before surrendering a leadoff homer to Tony Caldwell in the fifth.

The left-hander pitched out of trouble twice after that. Boyd helped him out in the sixth, making a leaping catch in center on what looked like it would have been a home run for Brian Fletcher.

Auburn put two runners on with one out in the eighth only to watch Harman strike out Trent Mummey and Fletcher to get out of the jam.

“They did what they needed to do to keep the momentum,” Pawlowski said.

Harman made a mistake that Morris clubbed for an opposite field homer in the ninth, cutting the Clemson lead to 5-2.

A single by Caldwell prompted a mound visit from Clemson coach Jack Leggett, who kept Harman in the game. The pitcher rewarded him by getting Gamache to ground into a double play and Ryan Jenkins to fly out to end things.

“This is the best I’ve felt all the way through,” Harman said.