By BOB BAUM
AP Sports Writer
TUCSON, Ariz. (AP) - Sabatino Chen made the biggest shot of his life _ and it didn't count.
The Colorado senior, 2 of 23 from 3-point range in his career going into the game, banked one in from behind the arc at the end of regulation for what would have been the game-winner, only to have officials wave it off after several minutes of review.
No. 3 Arizona, which had trailed virtually the entire game in its Pac-12 opener, went on to win 92-83 in overtime Thursday night to remain unbeaten.
Colorado coach Tadd Boyle maintained his composure with some difficulty afterward.
"I mean, are you kidding me?" he said. "It's disappointing because our team played well enough to win."
Arizona coach Sean Miller acknowledged the call "could have gone either way."
Some replays indicated the shot was taken in time. Others showed that perhaps it wasn't.
"It came down to fingertips, maybe," Chen said.
Boyle and his players at least had the satisfaction of knowing how well they had played compared with their debacle a month ago when they lost 90-54 at Kansas.
"I think our team grew up," Boyle said. "We are not satisfied. This is not a moral victory. We don't feel good about ourselves."
Chalk up another heart-stopping victory for Arizona, following a 65-64 win over Florida on Mark Lyons' layup at the buzzer and 68-67 over San Diego State on Nick Johnson's late block.
"We have a great group of guys but we can get a lot better," Johnson said. "We've escaped with some tough wins but we're going to go back to practice and get better."
This one was the most improbable of all. Arizona (13-0, 1-0 Pac-12) outscored the Buffaloes 10-2 over the final 1:35 of regulation to force overtime. The Buffaloes (10-3, 0-1) missed four of six free throws in that span.
"We would have gotten what we deserved if we had lost," Miller said.
When Chen banked in the 3-pointer, it looked like that would be the outcome. But after huddling for several minutes, the officials said no. Referee James Breeding told a television announcer that the ball was on Chen's fingertips when the lights around the backboard went on.
"If it's the wrong call, I'm really, really sick to my stomach," Boyle said, "because we had guys in this locker room that deserved to win that game."
The Wildcats were down by 17 points in the first half and 16 with 12:40 to go in regulation.
Askia Booker led Colorado (10-3, 0-1) with 18 points.
Arizona's 13-0 start is the second-best in school history and best since the Wildcats won their first 16 in 1932-33.
Chen scored a career-high 15 points, 12 in the second half. Josh Scott scored 15 points and Xavier Johnson had 13 for the Buffaloes, who beat Arizona by two points to win the Pac-12 tournament last season.
Lyons overcame an awful start to score a season-high 24 points, including two free throws that tied it at 80 with 9.2 seconds left in regulation.
Solomon Hill scored 15 points for the Wildcats. His 3-pointer with 1:35 to go in the second half cut the lead to 78-73.
Nick Johnson stole the ball from Andre Roberson and was fouled. Johnson made one of two free throws to cut it to 78-74 with 1:15 to play.
Scott made one of two free throws to make it 79-74 with 1:13 left. Lyons missed but Booker threw the ball away to Arizona's Jordin Mayes, whose layup cut the lead to 79-76 with 51 seconds on the clock.
Spencer Dinwiddie could make just one of two free throws with 44 seconds to go and it was 80-76. Lyons' driving layup cut it to 80-78 with 27 seconds to go.
Jeremy Adams was fouled and missed both free throws, then Lyons drove to the hoop, was fouled by Johnson and made both free throws as the crowd went crazy with 9.2 seconds left.
They fell silent when Chen banked in the shot at the end of regulation. But officials huddled around the monitor for several minutes before ruling the shot no good.
Parrom scored the first five points for Arizona in the overtime. His three-point play made it 83-82, the Wildcats' first lead since it was 5-4.
"We're playing with fire with the way that we're playing offense," Miller said. "We have talented players and we're trying to score against good defenses in January on the first three passes of a possession. It doesn't work that way."