LAS VEGAS -- Colorado won four games in four days to become a surprise winner of last year's Pac-12 tournament.
The Buffaloes took the first step toward another four-in-four run on Wednesday.
Spencer Dinwiddie scored 20 points and Colorado picked up a much-needed win at the Pac-12 tournament, holding off Oregon State 74-68 in the first of what it hopes to be four rounds.
"You can't come in with the big-picture mentality," Colorado coach Tad Boyle said. "We said that before the game. We're saying it after the game. That's just our approach and our mentality. These guys have bought in."
Colorado (21-10) needed a couple of wins in Las Vegas to boost its NCAA chances and got off to a good start by dominating Oregon State defensively most of the second half.
"We came here with one goal in mind and that was to beat OSU and survive and advance," Dinwiddie said. "So we did that little first step and we're going to continue to just try to move forward."
Oregon State (14-18), the No. 12 seed, pulled off one of the biggest upsets in Pac-12 tournament history by knocking off top-seeded Washington last year and dimmed Colorado's NCAA hopes with a win in Boulder last weekend.
The Beavers fell short of repeating either performance by struggling against Colorado's defense and athletic interior players.
Oregon State hit 7 of 25 shots from 3-point range, including 3 for 17 in the second half. The Beavers also were outrebounded 43-30, giving up 17 on the offensive glass that led to 18 points for Colorado.
"I think the real thing that had hurt us were the second chance points, offensive rebounds," Oregon State coach Craig Robinson said. "We played them at their place and we did a great job on the boards. We did not do as good of a job this time around."
Colorado entered the Pac-12 tournament on the NCAA bubble after losing its season finale to Oregon State at home last weekend.
Playing without Roberson, who missed his second straight game with a viral infection, the Buffaloes struggled against the Beavers, losing 64-58 right after knocking off then-No. 19 Oregon.
Oregon State had lost five straight before that and hadn't won in Boulder in six tries, so it was one of those late-season losses that won't look good on Colorado's resume when Selection Sunday rolls around. It also meant the Buffs lost a chance at getting an opening-round bye in the Pac-12 tournament, dropping the defending champions to the fifth seed.
Coach Tad Boyle was so frustrated by the loss that he grabbed a microphone and apologized to the fans after the listless performance in the final home game for Colorado's seniors.
The good news was that the Buffs only had to wait four days for the rematch.
It was ugly early.
Colorado missed eight of its first 11 shots, Oregon State opened 1 for 6, and the teams needed more than five minutes to crack double figures in combined points.
Luckily for the teams and their fans, the action picked up a little.
Colorado got little production from Roberson, who had 2 points on 1 of 3 shooting and two fouls in seven minutes.
The Buffaloes made up for his quiet half with 10 offensive rebounds that led to 11 points and a 32-26 halftime lead after Dinwiddie hit a half-court shot at the buzzer. The Beavers tried to get a last-second shot off, but turned it over, giving Dinwiddie just enough time to launch his shot.
"It definitely gave them momentum going into the half," Nelson said. "We were trying to foul and sometimes that's just how the ball rolls sometimes. It was a good shot. I mean, I was just hoping that it didn't go in. I was watching it and I was hoping, and it went in. They got momentum."
Oregon State didn't score in the final 2:42 of the first half and missed its first six shots of the second. The Beavers kept misfiring, falling behind 53-42 after missing 16 of 20 shots, including all 10 of their 3-pointers.
Colorado answered every rally attempt by Oregon State after that, hitting 11 of 16 free throws in the final 1:53 to earn a chance at picking up another important win.