Up four points at halftime, 44-40, Sam Houston started the second period with an 11-0 run and were up 53-43 after a basket by Sequeena Thomas at the 15:41 mark.
Seeded third, the Kats' highest women's seed in their 25-year Southland history, Sam Houston appeared headed to only their tournament semifinal appearance ever. But the wheels came off as the Kats went cold and Texas State heated up.
"The shots just didn't fall for us," said head coach Brenda Nichols. "I think we missed a couple of block outs, they played us well. We kept up the intensity and never gave up and I was proud of them for that."
The Bobcats tied the game at 57-57 and never trailed again.
Britni Martin hit a trey with 48 seconds left to cut the margin to 68-64. But No 6 seed Texas State hit eight consecutive free throws to ice the victory and advance to play No. 2 seed McNeese State Thursday.
Thomas led both teams with 25 points and 17 rebounds. Martin scored 17 points. Ashley Ezeh led Texas State with 24 points and Diamond Ford added 20.
Texas State jumped out to an early 5-0 lead and stayed ahead for most of the first half. Thomas gave SHSU its first lead of the game with a jumper as the Kats went up 35-34 with 3:45 remaining before halftime. The Kats ended the first period with an 11-6 run.
"We shot really well in the first half so I was a bit concerned about how we would come out in the second half," Nichols said. "it was just one of those nights."
Sam Houston hit 50 percent from the field (18-of-36) in the first half and three of their first four attempts in the second period. But in the final 15 minutes of the game, the Kats went 6-for-37 and ended the game with 35.1 percent from the field.
"We just needed to take better shots," Martin said. "I think we started forcing too many shots. If we would have changed anything it would be to just get to the line more. We didn't shoot enough free throws and we should have attacked more."
The loss marked the 10th time in Sam Houston's 12 appearances in the Southland post-season women's tournament that the Bearkats have fallen in the first round.
Sam Houston's back-to-back 17 victory seasons marks the most wins (34) in a two-year period for the program since SHSU joined the Southland Conference.