The Tigers posted the second low round of the tournament at the Tennessee National course on Sunday, a three-over-par 291, which is 18 strokes better than their day two score and 19 better than their opening day performance.
Shirley led the Tigers on Sunday with a two-under-par round of 70 that included three birdies and just one bogey. She finished in a tie for fourth place for the tournament at three-over-par 219, five shots off the pace by Stacy Lewis of Arkansas.
"All year Margaret has being trying to put together a great senior year," Auburn coach Kim Evans said. "It really came together for her at the tournament in Georgia last month and she got her game back. She played like a true veteran this weekend and made Auburn proud."
Candace Schepperle shot a 72 and finished in a tie for seventh with a 221 total.
Cydney Clanton and Mariana Macias each posted a 75 on Sunday. Auburn did not count the 76 in the team total shot by Abigale Schepperle.
Clanton totaled a 234 for 29th place. Macias finished at 238 and Abigale Schepperle shot a 240.
"Florida just played exceptional this entire tournament," Evans said. "We are still evolving as a team right now and it was nice to see it come together for us today. Overall it was a good tournament despite our first two days. We are still trying to piece everything together and our goal continues to begin to climb to the top."