KANSAS CITY, Mo. -- Usually the last player on the bench, Whitney Zachariason suddenly became Baylor's first option in a tougher-than-expected Big 12 tournament opener.
The junior forward scored a career-high 17 points as the Bears (No. 18 ESPN/USA Today, No. 16 AP) shook off 11th-seeded Colorado for a 72-65 victory Thursday night.
The sixth-seeded Bears advanced to a quarterfinal Friday night against 12th-ranked Oklahoma -- a game that will mark the return of suspended freshman star Brittney Griner.
With Griner out and Colorado playing a 2-3 zone defense, the Bears turned to the little-used Zachariason, who responded with five 3-pointers.
"You go with your gut, and Whitney, that's what she does best," Baylor coach Kim Mulkey said. "I couldn't be happier for a young lady who has sat the bench, has been the last one to go in ball games the majority of the year. She never, ever pouts, never thinks about herself. She thinks about the team."
Mulkey called on Zachariason about three minutes into the game, after Baylor had struggled with its shooting. She had shown in practice that she's one of the team's best shooters but hadn't gotten a chance to show it in a game until Thursday. She came in averaging five minutes and 1.4 points, and she had a total of three 3-pointers in her 18 games.
"If I go in a game, I'm probably going to go in to shoot," she said. "I think everybody knew we had to step up because we had a few people out."
The 11th-seeded Buffaloes, who lost 13 of 16 conference games, threatened to avenge a 34-point regular-season loss before Baylor put them away. Jordan Madden hit a deep 3-pointer with 39 seconds left to give the Bears (23-8) a six-point lead.
"She might miss four or five that she takes, and then she'll hit a big shot for ya," Mulkey said of Madden.
Brittany Spears had 24 points and Alyssa Fressle added 16 for Colorado (13-17), which was held without a field goal for the last 6:25 and lost its 23rd straight against a ranked team.
The Buffs finished with losses in 12 of their last 13 games.
Griner wore a Baylor sweatsuit and sat behind the bench, serving the second game of a two-game suspension for punching and breaking the nose of Texas Tech's Jordan Barncastle last week. The Bears also were without second-leading scorer Melissa Jones, who has battled injury the second half of the season.
Baylor won the regular-season meeting with Colorado 76-42 in Waco, Texas. Griner had 24 points, 10 rebounds and 11 blocked shots in that game.
Baylor lost 70-54 to Texas without Griner and Jones on Sunday, and looked headed for another defeat against the Buffaloes. Colorado led by as many as eight points in the second half and was up 62-58 when Chucky Jeffery scored with 6:25 left.
The Buffs didn't make another field goal against the nation's No. 2 team field-goal defense. Baylor turned up its pressure in the second half, when it forced 12 of the Buffs' 18 turnovers.
"The press changed the whole game, I guess," Spears said.
Baylor didn't have the game put away until Madden's big 3-pointer in the final minute.
"As far as the team, I know they're disappointed," Colorado coach Kathy McConnell-Miller said. "But they gave their heart. It's been a tough year, and we're going to move forward."