The Longhorns seemed to have it figured out. Starting with a 4-0 lead over Oklahoma State, an underwhelming regular season seemed to be in the rear-view mirror.

But, in a season filled with blown leads and late-game collapses, a 10-4 loss to the Cowboys on Wednesday was a fitting opener to the Big 12 tournament in Oklahoma City. That 4-0 Texas lead gave way to a Cowboys avalanche in the fifth, with an eight-run inning punctuated by a moonshot grand slam from Conor Costello.

By the end of the fifth, Oklahoma State tallied eight runs and five hits, and was the beneficiary of three Longhorns’ errors. A game that began so promising turned into a crushing defeat, one not unfamiliar to the burnt orange in 2016.

“We kind of put it all together in the worst way,” head coach Augie Garrido said. “That one inning is what really separated the game.”

Texas jumped on the Cowboys from the get-go, driving in two runs in the first. Sophomore designated hitter Travis Jones got the scoring started with an RBI double to deep center, scoring freshman outfielder Tyler Rand, who led off the game with a single and a stolen base.

Jones’ blast was immediately followed by the Longhorns’ third hit of the inning, coming off the bat of junior catcher Tres Barrera. Barrera — one of Texas’ premier hitters — smacked a single up the middle, scoring Jones. After one, the Longhorns led 2-0.

On the hill for the Longhorns was senior pitcher Ty Culbreth. Culbreth cruised through the first four innings on the mound, striking out six Oklahoma State batters while surrendering no runs and just three hits.

It was a dominant four innings from Culbreth, who shined in last year’s Big 12 tournament. His complete-game shutout of Baylor vaulted the Longhorns into the tournament’s championship game, which the Longhorns would ultimately win to send them to the NCAA regionals.

Seemingly cruising to victory, Texas’ lead dissipated in dramatic fashion in the bottom of the fifth. Oklahoma State loaded the bases with nobody out, and quickly capitalized. Three consecutive singles cut Texas’ lead to one, followed by Costello’s bomb to left center. All the momentum the Longhorns once held evaporated, and the sullen Longhorns returned to their bench down 8-4 after five.

“They really capitalized on all parts of the game in that rally,” Garrido said. “Getting an eight is hard to do.”

Oklahoma State added another run in the sixth and one more in the eighth, ending the contest in commanding fashion at 10-4. The season is still alive with the Big 12 Tournament being a double-elimination affair. But after Wednesday’s loss, ending the year on Thursday would be a merciful end to a season that has been anything but for the Longhorns.