UTA erased a 2-0 deficit in the match, but a 15-12 5th set gave the match to Texas State.
The two programs will meet for the 33rd consecutive year, with the Mavs holding a 42-31 edge in the series.
UTA extended its home win streak to five straight matches and 10 out of the last 11.
UTA out-hit, out-dug and out-blocked Georgia Southern in the four-set win.
UTA has won four in a row in Arlington, including its first two Sun Belt matches.
Diane Seymour has been the head coach of the UT Arlington volleyball program since 2004 and owns an overall record of 175-169. Seymour arrived at UT Arlington in 1984 as a student-athlete and later spent eight years (1996-2003) as the assistant coach.
Seymour ties to the UTA program stretch back three decades, helping lead the Mavericks to more than 400 victories, seven Southland Conference championships, six NCAA Tournament appearances and a No. 7 national ranking at the end of the 1988 season.
Seymour has directed UT Arlington to six double-digit winning seasons in conference play. During the 2014 campaign, Seymour helped guide the Mavericks to their best winning percentage since 2004 and most wins since 2006. She also helped UTA claim its first All-American since 1989 as Briana Sharratt was named an AVCA Honorable Mention All-American. She notched her 100th career victory in 2010 in a five-set match at Texas A&M-Corpus Christi. Her 150th win came in the Sun Belt Championship semifinals as the Mavericks swept Troy to advance to the championship match in the program's first season in the conference.
Seymour returned to her alma mater in 1996 as an assistant coach on Janine Smith's staff. In her eight years as an assistant, the team captured two regular season championships, two SLC Tournament titles and made two trips to the NCAA Tournament while never finishing lower than fourth in the conference.
After a successful year as interim coach in 2004, athletic director Pete Carlon named Seymour the sixth head coach in UT Arlington history on Nov. 22, 2004.
Seymour came to UT Arlington in 1984 as a student-athlete, but missed all of the season after undergoing knee surgery. She worked her way into the lineup in 1985 and contributed 18 kills, 24 digs, and 12 service aces in 24 matches as the team went 28-4 to make the program's first appearance in the NCAA Tournament.
Seymour captained the 1988 squad to 30-4 record and a No. 7 ranking in the final AVCA poll. The team earned tournament wins over Pepperdine and Kentucky before being eliminated by eventual national champion Texas. Seymour finished her playing career with 48 kills, 95 service aces and 433 digs in 119 matches and 313 sets. Including her redshirt season, the Mavs went 140-41 during her playing tenure.
Seymour arrived at UT Arlington after earning all-state honors at Arlington High School in 1983. She began her career at Arlington Bowie High School, playing for her college coach Lisa Love. Seymour earned a bachelor's degree from UT Arlington in 1989. After her playing career ended, Seymour worked closely with several of the top club teams in Texas and is currently the director of the North Dallas Junior Volleyball Association.