Oklahoma State jumped out quickly with first-half goals by Annika Niemeier and Katie Richardson while the Cowgirls’ defense shut down Nebraska’s high-powered offense 3-0 in the opening game of the Big 12 Conference Soccer Tournament Wednesday at San Antonio.

Kasey Langdon assisted on one of those goals and added her own score with 15 minutes remaining in the game. Adrianna Franch registered her ninth shutout in goal for OSU.

In pulling off the mild quarterfinal upset, fifth-seeded OSU (13-7-0, 6-5-0) will play the semifinals Friday at 5:30 p.m. against the winner of the Missouri-Kansas game played later on Wednesday.

Mizzou is the tournament’s top seed while KU did not make it into the bracket until advancing past Texas Tech in a play-in game Monday.

Fourth-seeded Nebraska (11-5-4, 5-4-2) entered the tournament ranked third nationally in scoring, but the Huskers were missing Morgan Marlborough, the freshman forward who on Wednesday was announced as the Big 12 Offensive Player of the Year and top newcomer.

Marlborough did not even leave the team hotel because she was suffering through flu-like symptoms. She’s the conference leader in points and goals scored, and her goals-per-game average of 1.11 and 2.58 rank second in the nation.

Without her, Nebraska was unable to mount much offense. In the decisive first half, the Cowgirls kept the ball in Nebraska’s end of the field most of the time. Both teams fired off five shots apiece, but the Cowgirls had two more corner kicks.

Langdon, an All-Conference senior forward from Wylie, Texas, got the scoring going 11 minutes in. Shortly after a throw-in, she put a centering pass over to Niemeier, whose kick to the heart of the goal got past Husker goalkeeper Tara Macdonald. It was Niemeier’s team-leading 10th goal of the season.

Richardson’s goal to make it 2-0 was unassisted. She scored from the right side when her kick was deflected by Macdonald, but hit the far post and ricocheted in during the 37th minute.

Langdon’s goal, her fifth of the season, put the game out of reach in the second half. She fended off a defender by going left, then through the defender to get the kick past Macdonald.