Clemson scored three runs in the top of the first inning, which was all that Harman would need as he struck out eight Auburn batters and issued just one walk.
"The biggest thing was for us to get some runs in the first inning," Harman said. "That really got us going. It was one of those days where everything was working for me and I?felt great."
Commenting on holding Auburn to five hits, Harman said, "They came in here on a high with a very good reputation offensively. I knew I had to make quality pitches and get ahead of the hitters to be successful.
"Fortunately, I was able to hit my spots and make some big pitches. I let my defense do work behind me and get us a victory."
Clemson head coach Jacket Leggett said Harman was the key to victory. "He threw strikes, mixed his pitches and got ahead of batters all night."
With Auburn suffering the loss to Clemson, Auburn must defeat Southern Miss and Clemson on Sunday and then defeat Clemson again on Monday to advance to the super regional round.
In other notes from Saturday night's game:
*Auburn is now 4-4 vs. Clemson in NCAA Regional matchups and 20-27 all-time in baseball games vs. Clemson.
*Sunday's 1 p.m. Auburn vs. Southern Mississippi elimination game will be the first time the Tigers and Golden Eagles have met in postseason play. Auburn has won the three previous matchups played in the regular season.
*Auburn will likely start lefty Cole Nelson on the mound vs. Southern Mississippi with Slade Smith having pitched in relief on Friday night. On May 15th vs. Tennessee, Nelson threw Auburn's first complete game shutout since 2005 when Josh Sullivan did it vs. VMI. It was Auburn's first shutout vs. an SEC opponent since 2002.
*As was the case on Friday night, Auburn fans packed Plainsman Park with a sellout crowd of 4,096 in the park and an estimated 1,500 watching from the parking deck in left field and beyond the right center field and right field fences.
*The grounds crew covered the infield with a tarp after Saturday night's game. The weather forecast for Sunday in Auburn is for a 50 percent chance of thundershowers for the 1 p.m. scheduled start of the Tigers vs. Southern Miss game. Tickets are available to the contest.
*SEC Player of the Year Hunter Morris picked up his first hit of the Auburn Regional with an opposite field home run in the ninth inning vs. Clemson. For it was his 22nd homer of the season to tie the school record set in 2000 by Todd Faulkner. Morris has 46 for his career.
*Clemson pitcher Casey Harman was the first left-handed starting pitcher to get a victory against Auburn this year at Plainsman Park. Auburn came into the game 16-0 at home vs. lefty starting pitchers.