STILLWATER, Okla. - Colorado's perimeter shooting was as good as it's been all season. Unfortunately, Oklahoma State's inside game, combined with timely outside shooting of its own, was just a little better.

Colorado drained 15 3-pointers and Chucky Jeffery recorded her second career triple-double but Oklahoma State's inside presence was the difference as the Cowgirls defeated the Buffaloes 78-70 in the quarterfinals of the 2012 WNIT Sunday afternoon at Gallagher-Iba Arena.

Colorado's season ends at 21-14 while OSU (20-12) moves on to host San Diego, 58-47 winners over Washington, on Wednesday in the semifinals.

The Buffaloes shot 47 percent from downtown (15-of-32) tying for the second-most 3-pointers made in school history. Senior Julie Seabrook and sophomore Brittany Wilson each had four and five players hit multiple bombs.

Jeffery ran the offense smoothly, helping the Buffaloes to their best point total since a 77-59 win over Weber State on Dec. 17. She finished with 12 points, 12 rebounds and tied a career high with 10 assists, her second career double-double and third in team history.

But Oklahoma State controlled the paint, outscoring the Buffaloes 44-14. Tiffany Bias, who scored a game-high 24 points, did a lot of the damage attacking the basket.

Big 12 Freshman of the Year Liz Donohoe and junior forward Toni Young also raised havoc near the basket. Donohoe had a double-double with 20 points and 13 rebounds. Five of her boards came on the offensive glass as the Cowgirls outrebounded Colorado 38-34. Young had 17 points, nine rebounds and four blocked shots.

OSU hit a scorching 58 percent of their 2-point shots (25-of-43), while CU made just 9-of-33 (27.2 percent) in that same area.

"I loved our effort and fight today," CU head coach Linda Lappe said. "Offensively, we haven't scored 70 points in a long time, the problem was defensively we couldn't stop them in the paint or off the drive."

The Cowgirls ran out to an 8-2 lead, but the Buffaloes started firing early and often. Brittany Wilson and Meagan Malcolm-Peck hit back-to-back 3's to pull CU to within 10-8. Ashley Wilson made four of her career-best six free throws to tie the game at 12.

After Seabrook hit a 3-pointer to trim OSU's lead to 16-15, the Cowgirls went on an 8-0 run with the help of layups from Bias and Kendra Suttles.

Oklahoma State had its largest lead of the first half at 36-23 before the Buffs closed the gap. Jeffery scored on consecutive possessions and Malcolm-Peck hit her second 3-pointer of the half as the Cowgirls led 40-33 at the break.

The Buffaloes scored the first five points of the second half, cutting it to 40-38 on Brittany Wilson's third 3-pointer, but OSU quickly extended its lead back to 10 thanks in part to consecutive layups by Bias, Donohoe and Young.

Oklahoma State increased its lead to 61-49 with 10:50 left in the game, but then started turning the ball over. The Cowgirls had turnovers on four straight possessions, which left the door open for Colorado, and the Buffaloes took advantage.

Seabrook scored seven straight points to spark a 12-0 run that ended with a Brittany Wilson 3-pointer and a 61-61 game with 6:46 left.

"We started executing our offense and we showed a lot of confidence even when we were down," Lappe said. "it never felt like that much, at the same time we could tell we were on the verge of going one of two ways -- we could either get down 20 or we could make it a game and go on a run. You have to love our players' heart and determination, to have the fight within them to make it a game."

As good as Oklahoma State had been inside all day, the Cowgirls received clutch outside shooting when they needed it most. Suttles broke the tie with OSU's first 3-pointer of the day. Donohoe then matched Suttles effort, drilling a 3-pointer to put OSU back up by six.

"I am so proud of our effort," Seabrook said. "It was really physical in there and we stepped up to the challenge. We let some offensive rebounds go in the first half, but we responded in the second half. We got it going on offense, stepped up and made plays."

Lexy Kresl hit the first of her three late 3-pointers, to put the margin at 67-64, but the Buffaloes went cold after that missing their next seven shots. Oklahoma State took advantage with a 10-0 run, finished off by a Bias fastbreak layup.

Seabrook ended her career in style with a team-high 16 points on 6-of-11 from the field. She tied personal bests for 3-pointers made and attempted going 4-of-6 on the afternoon. Seabrook started all 69 games played under coach Lappe's staff and proved to be a great leader for the younger Buffaloes.

"Julie is the epitome of what we want in a Colorado women's basketball player," Lappe said "She does all the right things on and off the floor. She plays hard and comes to work every day trying to get better. She is always striving to be the best in whatever it is she is doing.

"I thought all season long, and for the last two years she gave us the leadership that we needed."

Brittany Wilson finished with 14 points, her four 3-pointers also tying a career high.