Colorado is ranked for the first time in over 15 years.
Air Force is one victory away from reaching 6-0 for the first time in 30 years.
These unbeaten teams needed overtime to decide last season's matchup and a raucous atmosphere is expected Sunday night when the No. 23 Buffaloes host high-scoring Michael Lyons and the surprising Falcons.
Colorado (4-0) moved into the rankings after an impressive showing last week in winning the Charleston Classic, knocking off Dayton, then-No. 16 Baylor and Murray State. The Buffaloes are seeking their first 5-0 start since 1989-90.
The last time Colorado was ranked was when it was No. 24 in the final poll in 1997.
"I think it means something to our players, I think it means something to our fans," coach Tad Boyle said. "One of the things that you do talk about as you build a college basketball team is gaining respect and I think being in the Top 25 legitimizes you to some degree but we can't let that go to our heads and so as a coach, you caution the overconfidence factor."
Air Force can record its first 6-0 start since 1982-83 as it continues to shine in its first full season under coach Dave Pilipovich. The Falcons boast an all-senior starting lineup and will be out for revenge following last season's 76-73 overtime home defeat to the Buffaloes.
"We love that game, it's a great rivalry to play an in-state team, a Pac-12 team, it's going to be on the Pac-12 network so that probably will be our toughest test to date," said Pilipovich, whose team was picked to finish last in the Mountain West Conference.
Lyons is the star for Air Force, averaging 22.2 points after he had 29 in Wednesday's 86-72 win over Montana State. He scored 31 against Colorado last season for his best effort of 2011-12.
The Falcons probably won't recognize Buffaloes top scorer Askia Booker, who scored 11 points as a freshman reserve in last season's matchup. Booker is averaging 17.8 points after his 23-point performance in last Sunday's 81-74 victory over Murray State capped his tournament MVP run.
The guard is shooting 50.0 percent after finishing 2011-12 at 40.2.
"I'm a better jump shooter," Booker told the Buffaloes' official website. "I put in a lot of hours in the gym this summer. Overall, it's confidence. That's a big thing in anyone's game ... I'm not saying I'm cocky, but I believe it's going to go in when I shoot it."
Booker is the first Colorado player to lead the team in scoring in three straight games since Alec Burks did it in five straight contests in 2010-11.
The Buffaloes are 8-1 at home all-time against the Falcons, who won 84-46 in their last visit to Boulder on Nov. 18, 2006.
"Now we come back off the Charleston tournament with a lot of momentum and Air Force is a good team, it's going to be a great game, a lot of good players on both sides so it should be fun," Boyle said.
