LAS VEGAS (AP) Faced with a game it could not afford to lose, Colorado came out flat at both ends. The Buffaloes were disjointed on offense, unable to stop Washington State on defense.

Once the second half started, senior Derrick White took over, helping Colorado avoid what could have been an NCAA Tournament-killing loss.

Derrick White scored 17 of his 26 points in the second half, Xavier Johnson added 19 and Colorado rallied from a shaky first half to beat Washington State 73-63 Wednesday night in the first round of the Pac-12 Tournament.

''Derrick White is one of the best players in this league,'' Colorado coach Tad Boyle said. ''Anybody that hasn't seen him play is missing something because he's special, and he showed why he's special tonight in the second half. Just made big plays for us.''

Colorado (19-13) got off to a miserable start at both ends as Washington State raced out to a 19-point lead. The seventh-seeded Buffaloes whittled into the lead by halftime and overtook the Cougars in the second behind White.

With White shooting and dishing, Colorado hit 15 of 28 shots in the second half to complete the comeback, earning a spot in Thursday's quarterfinals against No. 7 Arizona.

''I was really proud of our guys for their second-half effort,'' Boyle said. ''I thought there were some really critical plays there down the stretch.''

Washington State (13-18), the tournament's No. 10 seed, lost all its mojo after a stellar first half, leaving coach Ernie Kent frustrated and ending the team's four senior starters disappointed in their final game.

Charles Callison and Ike Iroegbu scored 16 points each, and Josh Hawkinson had 12 points and 12 rebounds.

''They hunted us down well in the second half,'' Kent said. ''We had a very difficult time with White again. We've had a hard time with him in all three games. To Colorado's credit, their experienced just stepped up and showed.''

Colorado entered the Pac-12 Tournament with NCAA Tournament aspirations and could not afford an early exit in the Pac-12 Tournament after closing the regular season with eight wins in 10 games.

The Buffaloes split with Washington State during the regular season, losing by two in overtime on the road, winning by 32 at home.

Washington State was the team looking for a blowout once the teams hit the floor in Vegas, using a 16-2 run to go up 25-9 midway through the first half.

The Buffaloes started to fight back late in the half, closing within 41-27. The Cougars hit 17 of 30 shots in the half, including five of eight from 3-point range.

Colorado picked it up even more to start the second half, hitting five of its first eight shots to pull within 45-42 in the opening five minutes. White had 13 points in that stretch.

The Buffaloes tied it at 49 and kept pushing, going up 59-52 on Johnson's three-point play on a tomahawk dunk in transition and pulled away over the final 90 seconds.

''In the first half I thought we were excellent at keeping them under wraps,'' Kent said. ''Second half we got a little bit fatigued and he really made us pay.''

BIG PICTURE

Washington State will have some holes to fill next season with four senior starters on this year's roster.

Colorado can't afford to get off to another slow start against Arizona in the quarterfinals or risk getting blown out.

UP NEXT

Colorado will face No. 7 and second-seeded Arizona in the quarterfinals on Thursday.

Washington State's season is finished.

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