OKLAHOMA CITY — Lindsey Vandever had a tough day behind the plate.

The Oklahoma catcher had two throwing errors that scored runners from third base, including one in the seventh inning that proved to be the winning run, and Nebraska upset Oklahoma 6-5 in the Big 12 tournament quarterfinals Saturday at ASA Hall of Fame Stadium.

With two outs in the seventh inning, D.J. Mathis had Darcy Rutherford down 0-1 in the count. Vandever then tried to pick off Whitney Barrett at third base, but her throw was off target and went off Jessica Legendre’s glove and into left field, allowing Barrett to score and put the Huskers up 6-4.

Mathis then struck out Rutherford.

It was eerily similar to the first inning, when a missed squeeze bunt left Rutherford hanging off third. Vandever’s throw to Legendre went wide that time, too, and Nebraska’s second run was allowed to score.

“That’s an aggressive catcher trying to make a play,” OU coach Patty Gasso said. “They were mistakes, but you really can’t fault her for being aggressive and trying to make a big play for us. I wouldn’t want her to be any different.”

Vandever’s miscue in the seventh proved to be the decisive moment of the game.

On her second pitch of the bottom of the seventh, Samantha Ricketts hit her second home run of the game, a solo shot to right field, that would have tied things up. Vandever, obviously frustrated, was on deck and slammed Ricketts’ bat into the dirt as the first baseman was rounding the bases.

Vandever would reach, though, as would Savannah Long. But with runners on second and third with one out, the Sooners couldn’t bring in the tying run.

“They’re fighters,” Gasso said. “They know how to play in this tournament. They’re a team like many, who are just trying to get hot to keep their season alive.”

Sub-par performances from pitchers Lauren Eckermann and Jadyn Smith helped put OU in a 5-3 hole before Gasso brought in ace D.J. Mathis. Eckermann gave up two hits and one earned run in her 12⁄3 innings, and Smith replaced her, only to give up three earned runs on three hits in her 11⁄3.

“Lauren just didn’t have it working early,” Gasso said. “We could see that and our catcher could see that. Going in with Jadyn gave D.J. a little extra time to rest.

“I thought it was early enough in the game that we could make a comeback … I wouldn’t do it differently. Throwing D.J. every game and going into a regional with her being tired is not what we want.”

The Sooners had their opportunities to take over the game. They left 10 baserunners stranded, including a fifth-inning opportunity with one out and the bases loaded that ended in an unassisted double play.

Ricketts was 3-for-3 with two home runs, a double and four RBIs. But she was the only one who came through in the clutch for OU Saturday.