Las Vegas, NV (SportsNetwork.com) - Colorado's Xavier Johnson drove along the left baseline and leapt into the air before cocking the ball back for a potential thunderous slam.
Then he met Aaron Gordon at the apex and the Arizona forward sent it back, and the Wildcats put the game away shortly thereafter.
Nick Johnson had 16 points and No. 4 Arizona pulled away in the second half to beat Colorado, 63-43, in the semifinals of the Pac-12 Tournament.
The Wildcats (30-3) netted 11 straight points following the Gordon block to turn an eight-point advantage into a healthy 51-32 margin just past the middle stage of the second half.
T.J. McConnell tallied 12 points and five assists, Rondae Hollis-Jefferson provided 12 points and eight rebounds and Gordon added nine points, nine boards, three blocks and three steals for top-seeded Arizona, which will face UCLA in Saturday's Pac-12 title game.
"Tale of two halves for us," Arizona head coach Sean Miller said. "I thought the first half, our defense was good, and our offense was really very, very average. We struggled. Our defense became great in the second half, but our offense found its flow. We shared the ball. We were more ourselves."
Askia Booker supplied 12 points and six boards for the fifth-seeded Buffaloes (23-11), who defeated USC in the first round and California in the quarterfinals.
The Wildcats were up 40-32 with 13 1/2 minutes left before Gordon's emphatic block. Hollis-Jefferson then put in a pair of baskets to begin the surge before McConnell nailed a right-wing triple. Gordon then had a tip-in and Jordin Mayes drove in for a layup to cap the surge and put Arizona comfortably ahead with 7:58 to play.
"That thing got away from us quick," Colorado head coach Tad Boyle said.
Arizona led by as many as 22 down the stretch.
Earlier, a McConnell 3-pointer finished off an 8-0 burst that staked the Wildcats to a 22-13 cushion with 6:09 left in the first half.
Colorado answered with an 11-2 run to tie the game at 24-24, but a Gabe York triple sent Arizona into the half with a 3-point edge.