LAS VEGAS (KGUN9-TV and AP) - Allonzo Trier scored 23 points, Ryan Anderson had 17 points and 11 rebounds, and No. 15 Arizona held on to beat Colorado 82-78 on Thursday in the Pac-12 tournament quarterfinals.
Arizona (25-7) overwhelmed Colorado in the first half before laboring through most of the second.
The third-seeded Wildcats allowed the Buffaloes to cut a 22-point lead to two on George King's 3-pointer with 3 seconds left.
Gabe York followed with two free throws to close it out, sending Arizona into Friday night's semifinals against No. 8 Oregon.
"We have to put two halves together," said York. "It's March. We have to more than just a one half team at the end of the day."
"It was just an emphasis early to match their physicality," added Ryan Anderson. "We did a good job of that in the first half but not in the second half. We need to do a better job of that and we have a good matchup tomorrow."
Colorado (22-11) clawed its way back from a huge hole by hitting the offensive glass (25), but couldn't overcome its shaky shooting. The fifth-seeded Buffaloes shot 34 percent and made 5 of 19 from 3-point range, leaving their NCAA Tournament fate in the hands of the selection committee.
King had 22 points, and Josh Scott finished with 16 points and 13 rebounds for Colorado, which had 26 second-chance points.
Oregon defeated the Wildcats earlier this year in McKale Center, the only team to do so in three years.