Down 5-3, the Bearkats fought back to take the lead for the first time on a three-run homer by third baseman Kevin Miller in the top of the eight. But the Mavericks tied the contest 6-6 on a RBI single by left fielder Preston Morrow in the bottom of the eighth to set up Beck's winning play.
The Kats had the bases loaded with two downin the top of the ninth but could not get the run across as a close call at second base was ruled as the third out.
Sam Houston (38-20) now must wait until Monday to learn if the Southland Conference regular season champions will receive an at-large berth in the NCAA regionals. The Bearkats stood No. 49 in the NCAA Division I RPI rankings last week. SHSU was attempting to become only the third No. 1 seed to win the tournament title in the 20-year history of the event.
UT-Arlington (35-23), the No. 4 seed, will advance to the championship final Saturday.
Opening the bottom of the first inning with a walk by center fielder Jake Pinchback and a single by shortstop Ryan Walker, UTA jumped in front 2-0 on successive RBI ground outs by right fielder Preston Beck and second baseman Michael Guerra.
Sam Houston got the first run back in the top of the second inning as first baseman Ryan O'Hearn led off with a double down the left field line and scored on another double to left by right fielder Jake Arrington.
Arrington tied the game 2-2 in the bottom of the fourth inning with a sacrifice fly caught at the wall. The play scored O'Hearn who again led off with a hit, singling then reaching third on a single by designated hitter Anthony Azar.
Maverick designated hitter Matt Shorthall put UTA right back in front, leading off the fourth with a home run to left field. After catcher Greg McCall was hit by a pitch, the Mavs added another run on an RBI single by shortstop Ryan Walker to take a 4-2 lead.
Shorthall, who led off the sixth taking first after being hit by a pitch, scored on a single by third baseman Travis Sibley to give UTA a three-run lead.
Arrington tripled to start the bottom of the seventh, scoring on a ground out by second baseman Ryan Farney to cut the Maverick margin to 5-3.
The Bearkats took their first lead in the top of the eighth as Miller blasted his second home run of the tournament to score center fielder Colt Atwood and left fielder Luke Plucheck who led off the inning with back-to-back singles. Miller became only the third Bearkat to hit two home runs in one Southland tournament. Bobby Verbick (2008) and Mark Wyatt (2009)were the first to accomplish the feat.
UTA bounced right back again on an RBI single by third baseman Travis Sibley tied the contest 6-6.
Michael Burchett (3-3) was the loser in relief for the Bearkats. Adam Boydston (2-3) earned the victory. The two teams combined for 23 hits with UTA holding a slight 12-11 edge.