These teams also split their last two regular-season matchups and will open conference play Thursday night in Tucson.
The third-ranked Wildcats (12-0) have matched their best start since the 1987-88 team opened with 12 victories en route to the Final Four. Arizona is now seeking to start with 13 wins for the first time since the 1931-32 squad was 16-0.
Colorado (10-2) enjoyed a successful first season in the Pac-12 in 2011-12, going 11-7 before capping a run through the conference tournament with a 53-51 victory over Arizona in the title game. That prevented the Wildcats from gaining an NCAA tournament berth.
Arizona has won all 12 conference openers at home since it joined the Pac-10 in 1978.
"We know that it's going to be a war," coach Sean Miller said. "I think at the end of the day when the Pac-12 season ends, Colorado will be right there. It's important that we're ready here, especially with our game being at home."
Arizona was severely tested in a 68-67 victory over then-No. 17 San Diego State last Tuesday in the championship game of the Diamond Head Classic. Nick Johnson blocked a layup attempt by Aztecs guard Chase Tapley in the closing seconds to preserve the victory.
Solomon Hill scored 21 points and was named tournament MVP. Hill averaged 13.0 points and 9.7 rebounds in the three meetings with the Buffaloes last season.
Thursday marks the Pac-12 debut of Mark Lyons, a Xavier transfer averaging 13.4 points to lead Arizona. Freshman starters Brandon Ashley and Kaleb Tarczewski are other newcomers that have made the Wildcats an improved team.
Colorado has won three straight, posting a 98-51 victory over Northern Arizona on Dec. 21 and an 80-52 rout of Hartford on Saturday in its last two games - both at home. The Buffaloes know things will get more difficult now.
"They've got men, they've got animals in there and it's a different deal than what we've faced the last two games," coach Tad Boyle said of Arizona. "But our guys understand that and our guys love challenges, they're competitive and they believe in themselves and we can't put too much into any one game."
The Buffaloes, ranked for two weeks earlier this season, feature four players who average double figures in points. Askia Booker is scoring 14.8 per game and Spencer Dinwiddie 14.4, with the two combining to make 41 3-pointers.
Dinwiddie scored a team-best 14 points in the conference title game against Arizona.
"I think Spencer Dinwiddie has developed from early in his freshman year to right now," Miller said of the sophomore. "He's a fantastic shooter. There aren't many players that play the game like him in college basketball."
The Buffaloes have dropped two of three road contests, falling 90-54 to then-No. 9 Kansas on Dec. 8 in their lone away game against a ranked foe.
"We need to be better in the true road games, that's been our Achilles' heel," Boyle said.