Colorado nearly pulled out a victory at Arizona's McKale Center last season, coming within a disputed 3-pointer of beating the Wildcats.
The Buffaloes had little chance of a repeat performance after getting off to a slow start against the nation's No. 1 team.
Colorado started flat and had no rhythm offensively until late, unable to overcome a big early deficit in a 69-57 loss to top-ranked Arizona on Thursday night.
"We were playing the No. 1 team in the nation, but they weren't that good," Xavier Johnson said. "We didn't come in here with the (right) mindset and it's hard coming into this atmosphere."
Arizona (19-0, 6-0 Pac-12) had a week off after blowing out rival Arizona State and was still in a groove early, building a 14-point lead in the opening six minutes.
The big lead allowed the Wildcats some leeway in the second half when things didn't go quite as well.
Arizona struggled from the perimeter, making 3 of 15 from 3-point range, had a rare night when it didn't outrebound the opposition (32-32) and missed three free throws in the closing 72 seconds to keep the game from becoming a rout.
The Wildcats pulled it out thanks to the big start and 44 points in the paint, allowing them to tie — with the 1992-93 and 1997-98 teams — for the longest winning streak in school history.
Nick Johnson led Arizona with 18 points and Aaron Gordon added 12.
"This is why we love McKale; we feel like it's like this all the time," said Arizona forward Brandon Ashley, who had 15 points.
Colorado nearly beat the Wildcats at McKale Center last season, losing in overtime after the officials waved off Sabatino Chen's banked-in 3-pointer at the buzzer in regulation.
The Buffaloes (15-5, 4-3) had no chance for late-game heroics in its third game without leading scorer Spencer Dinwiddie.
Colorado struggled to slow Arizona's bevy of scorers and couldn't shoot its way out of the big early hole, falling to 0-16 all-time against No. 1 teams.
Xavier Johnson led the Buffaloes with 21 points and Josh Scott added 15 with 11 rebounds.
"We dug ourselves a hole," Colorado coach Tad Boyle said. "We had trouble scoring the ball and they made shots. We didn't have an offensive rhythm all night."
The Buffaloes split their first two games without Dinwiddie, losing to UCLA and beating Southern California after the junior sustained a season-ending left knee injury against Washington on Jan. 12.
Arizona was a much stiffer challenge without Dinwiddie, Colorado's scoring and assists leader.
The nation's top-ranked team for seven straight weeks, Arizona entered the game fifth in scoring defense (56.7 points) and shooting percentage against (37 percent) and was 22nd at defending 3-pointers (29 percent).
Colorado needed someone to step up and no one was able to do it early against Arizona's relentless pressure.
Barely able to get passes off much less good shots, the Buffaloes missed their first five shots and had four turnovers in the opening six minutes.
Arizona also missed its first five shots, but started dropping them in from all over, building a quick 18-4 lead.
The Buffaloes settled down for a little bit, cutting the lead to six with a 10-2 run.
All that seemed to do was make the Wildcats play harder.
Ratcheting the defensive pressure back up, Arizona hounded the Buffaloes into more missed shots and turnovers, leading to breakouts and 3-pointers at the other end.
Starting with a 12-2 run, the Wildcats built the halftime lead to 39-24, holding Colorado to 8-of-27 shooting while forcing nine turnovers. Johnson had 12 at the half and Ashley nine.
"We do what we've been doing, just focusing on the process of Arizona basketball and that's just a little glimpse of what we can do," Gordon said.
Colorado had a little more success shooting to start the second half, hitting three of its first four shots.
Problem was, the Buffaloes couldn't stop the Wildcats.
Arizona hit its first six shots, including one by Ashley that bounced off Scott and into the basket and a reverse dunk off a spin move by Gordon that put the Wildcats up 51-31.
The Wildcats made 12 of 22 shots in the second half to prevent Colorado from cutting the lead under double digits.
"Our second half maybe wasn't as good as our first, but there are always good lessons to be learned from that and still leave with the win," Arizona coach Sean Miller said.