By Wendell Barnhouse
Big12Sports.com Correspondent

TULSA, Okla. – Oklahoma State made sure that the upset trend ended at three.

The first three games of the Phillips 66 Big 12 Baseball Championship Wednesday resulted in victories for the underdogs. The second-seeded Cowboys got excellent pitching and timely hitting from a local favorite to put away No. 7 seed West Virginia, 3-0.

It was the first time in 17 years of Big 12 Championship play that the Cowboys threw a shutout.

"That's impressive, really impressive," Oklahoma State coach Josh Holliday said. "(Cowboys pitching coach Rod Walton) is as good a pitching coach as there is in college baseball. Our pitchers are coached well, have mental toughness and are prepared with great game plans."

Conor Costello, making just his fifth start, went four scoreless innings. He was able to escape three times when the Mountaineers put runners at second and third. The teams that won the first three games all scored first.

"We lost the game in the first four winnings," West Virginia coach Randy Mazey said. "If we had touched home as much as we touched third we would have won."

In the first inning the Mountaineers had runners at second and third with no outs but Costello worked out of the jam. WVU's Kyle Davis was at third but slipped trying to tag up on a fly to right.

"I take full blame for that," he said. "Three times guys are up there second and third and we don't get the hit we needed - that was devastating."

Oklahoma State played small ball to score the first run. With two outs, Corey Hassel singled and scored second. Donnie Walton, playing in his hometown, then drove in Hassel with a single through the right side.

"I'm feeling comfortable at the plate," he said. "I like coming back here. Good to be back to see all my high school buddies."

The Cowboys extended their lead in the fourth. Dustin Williams, who struck out with two runners in scoring position in the first, led off the inning with a homer to right field. Oklahoma State threatened to produce a big inning but the Mountaineers flashed some leather.

Tim Arakawa followed Williams' homer with a single and then the Cowboys put on the hit and run with Ryan Sluder. His hot grounder up the middle was gloved behind the bag by West Virginia shortstop Taylor Munden. He had to make his force out flip to second baseman Shaun Corso between his legs, shotgun snap style.

Walton tacked on an insurance run in the bottom of the eighth with a deep drive to right for his fourth homer of the season.

Trey Cobb, who is from nearby Broken Arrow and like Walton was basically playing in his old backyard, was a lock-down reliever, working five hitless innings to stifle West Virginia.

"Trey's outing was outstanding," Holliday said. "His command was big-time and he was very much in control of the game. We had two guys who pitched extremely well and we played excellent infield defense."

Oklahoma State advances to face No. 6 seed Kansas State at 7:30 p.m. Thursday. The Wildcats knocked off third-seeded Oklahoma, which will now take on West Virginia at 12:30 p.m. Thursday.