NASHVILLE, Tenn. (AP) — South Carolina coach Frank Martin thinks his Gamecocks are finally in a good place mentally, and the results are showing on the court.

Sindarius Thornwell scored 18 points and tied his career-high with four 3-pointers as South Carolina held off Missouri 63-54 Wednesday night in the Southeastern Conference tournament.

The 11th-seeded Gamecocks (16-15) now have won three of their last four, and this gives them their best season since winning 21 in 2008-09. They will play sixth-seeded Mississippi on Thursday night.

"We've started worrying about all the things that matter and not the things that don't matter," Martin said.

"Guys have stayed very positive through difficult times and difficult games, and we had to learn. We had to learn. I think, and I could be wrong, the success in nonconference play, we didn't have guys who understand how to manage that. And when we lost a couple league games early, we had guys started pressing. And I didn't do a very good job early ... helping them through that."

Michael Carrera added 12 points for South Carolina despite being limited to 22 minutes with four fouls.

Missouri (9-23) finished the season having lost 16 of 18 games. The 14th-seeded Tigers sure made it interesting not letting South Carolina run away. They got within a possession seven times in the second half, the last at 52-50 when Montaque Gill-Caesar hit two free throws with 6:42 to go.

Carrera answered with a jumper to start an 11-1 spurt as South Carolina pulled away.

"We feel like we can come in and compete and have a chance to win these games coming up," Thornwell said.

Gill-Caesar finished with a team-high 10 points.

"I thought we played extremely hard," first-year Missouri coach Kim Anderson said. "Obviously, we made too many mistakes at critical times. We had a chance to get the game tied, we had a chance to get it close a few times, we threw the ball away. But by and large, I thought our effort was good. Our execution wasn't very good at times, but I think South Carolina had something to do with that."

Carrera's lone 3-pointer was part of a strong offensive start that quickly separated the Gamecocks from Missouri. South Carolina made its first three attempts and eight of its initial 14, opportunities created by good energy and ball movement.

Missouri, meanwhile, began just 1 of 6 from the field and things didn't get much better in a first half. Though the Tigers were slightly less error-prone than the Gamecocks (8-7), they missed passes near the basket and seemed out of sync for the most part.

South Carolina took advantage to build its biggest lead at 30-17 before Missouri regrouped for a 7-0 run over the final two minutes to trail by just 30-24 at the break. The Tigers' task was containing Carrera and Duane Notice, whose 13 combined points symbolized the Gamecocks' 45 percent shooting.