The 20th-ranked Buffaloes gave up a season high in points in losing 78-73 to the seventh-ranked Cowboys in an MGM Grand Showcase Benefiting Coaches vs. Cancer Tournament game Saturday night.
Colorado's previous season-high in points allowed was 72, by Baylor and Kansas. The Buffaloes (10-2) also were just 1 for 2 from the free-throw line in the first half, after coming into the game eighth in the nation in attempts and points from the free throw line.
"For whatever reason, obviously, we've got to figure a way to score when we're not getting to the free throw line," Colorado coach Tad Boyle said. "That's frustrating."
The Buffaloes made just 35 percent (11 for 31) of their field-goal attempts during the first half and then had to withstand 13-for-21 shooting by Oklahoma State (11-1) in the second half.
"When you allow a team to shoot (62) percent in the second half, it's going to be tough to beat them," Boyle said. "To play the No. 7 team in the country and not feel good about it, but still only lose by five points, there's something about this team. There's a lot of fight in them. They keep coming."
On the bright side for the Buffaloes, Askia Booker had a season-high 13 first-half points on 5-for-9 shooting. He also went a season-best 3 for 5 from 3-point range during the first 20 minutes.
Markel Brown scored 23 points and had 11 rebounds to lead Oklahoma State, while Marcus Smart had 18 points and Phil Forte added 16 points—making 4 of 7 from 3-point range—for the Cowboys, who shot 52 percent from the field overall.
Le'Bryan Nash had 15 points, six rebounds, and three blocked shots as the Cowboys' win snapped Colorado's 10-game winning streak. Brown scored 11 points from the free-throw line to help lift Oklahoma State to its fourth straight win.
Josh Scott led Colorado with 20 points, 12 rebounds, and three steals. Booker scored 19 points and Spencer Dinwiddie added 18.
"They shot 62 percent in the second half, and we didn't have enough to beat the No. 7 team in the nation," Scott said. "They set a lot of screens and have a lot of good players. We were there with them. We didn't play our best game."
Oklahoma State built its lead to 63-53 with 7:36 remaining. Colorado chipped away and brought the deficit to four points twice in the final minute, but couldn't get any closer.
Booker had 13 first-half points for Colorado, which trailed 32-26 at halftime. The Cowboys took the lead for good with 1:37 left in the opening half.
Colorado will be back at the MGM Grand Arena for the Pac-12 Conference Tournament in March.
The Cowboys lead the series 61-48.
The teams last met in January 2011 with the Buffaloes winning 75-71.
Colorado hasn't beaten a top-10 team on a neutral floor since the 1990 Big Eight Tournament in Kansas City.