Bill Self noticed something different about Allen Fieldhouse Sunday afternoon.

And it wasn’t the ice on the windows.

It was the 2,000 or so seats that went unoccupied during his No. 12-ranked Jayhawks’ 78-57 victory over unranked Colorado, a game played in the aftermath of a nasty early morning ice storm.

“I thought, ‘The weather’s bad, and I hope that’s why,”’ Self, the Jayhawks’ coach, said of his initial reaction to all the unused tickets.

He wasn’t sure what his players thought of the less-than-capacity gathering, however, so he addressed the issue during a pregame pep talk.

“The players walk out there, and there’s more empty seats than they’ve played in front of in a long time. In their minds are they thinking, ‘Is it because we lost our last game and didn’t play well?”’ Self said, referring to Thursday’s shocking home loss to Richmond.

“I talked to them about how many people were here considering there’s three inches of ice on the streets and said, ‘Let’s go make our energy, and let’s give these guys a show.”’

Message received.

The Jayhawks rewarded the 14,500 or so fans who braved the slick streets by skating on offense and clamping down on defense in improving to 12-3 overall and 4-0 in the Big 12 Conference.

CU dropped to 10-6, 2-3.

Kansas University players, from left, Christian Moody, Jeff Hawkins and Michael Lee share a laugh during the waning moments of the Jayhawks' 78-57 victory over Colorado. KU's rout of the Buffaloes Sunday was its 21st straight victory over CU at Allen Fieldhouse.

“We didn’t feel like we had to prove anything. We wanted to handle our business,” said junior forward Wayne Simien, whom Self called “a monster on the defensive boards” after grabbing 15 rebounds to go with 20 points.

“We came out hungry. With bad weather, there still were a lot of fans in the fieldhouse, and that meant a lot to us,” Simien added.

The fans had a grand time watching KU hit eight threes — most since a 10-trey effort at TCU Dec. 1 — while holding CU’s Michel Morandais and Blair Wilson to 13 points off 4-of-22 shooting.

KU totally frustrated Buffs’ center David Harrison, who scored five points in 14 foul-plagued minutes.

“Four guys traded off guarding Wilson and Morandais, and those guys were 4-of-20,” Self said, lauding J.R. Giddens (three threes, 13 points), Keith Langford, Aaron Miles and Michael Lee. “Our defense was really good in holding them to 11 points the last 15 minutes of the first half.”

Colorado missed 14 shots in a row at one point and trailed 41-21 at the break.

“Our defense wouldn’t have looked as good if Harrison was in the game, probably,” Self said of Harrison, who picked up two quick fouls and played just eight minutes the first half. “He forces double-teams and all that stuff. With him out of there, we didn’t have to trap.”

KU goes from yuck to yuks Woodling: CU’s Harrison needs to grow up ‘Real’ KU shows up Big Buffalo bristles WIBW video: Jayhawks cruise over Colorado Hear Bill: KU-CU postgame comments See the photos: KU-CU photo gallery Get the stats: KU-CU box score

Harrison eventually fouled out with 10 1/2 minutes to play and was banished to the locker room by CU coach Ricardo Patton after Harrison and fans behind the visitors’ bench engaged in arguments.

“It’s an emotional game. Harrison is an emotional guy,” Self said. “I think it’s a hard game for him to play because there have to be fouls called. When Jeff Graves and David Harrison are banging out there, there will be fouls called. When fouls are called, frustration sets in.”

Knowing fouls would be called, Self let high-scoring Simien guard Lamar Harris, not the aggressive Harrison.

That left Graves and David Padgett — who combined for just 12 points and four rebounds — to hound Harrison.

“Coach kept me off Harrison to keep me out of foul trouble,” Simien said. “Even though David and Jeff’s stat lines weren’t that great, they did a great job on Harrison getting him into some early fouls, getting him frustrated and out of the game.

“They did as good a job as anyone out there.”

Self had no problem with Harrison heading to the showers with 10 minutes to play.

Kansas' Aaron Miles, left, beats Marcus Hall for a layin.

“If somebody is emotional, which he obviously was emotional with the fans, I think it’s a great move by their coaching staff, a smart move,” Self said. “You totally eliminate anything negative that could potentially occur. People may say it didn’t look good. I don’t know what they are saying. I am in total agreement with the way Ricardo handled the situation.”

Self said he was aware Harrison was not a favorite of KU’s fans because of comments he has made in the past.

“I heard the fans have really taken notice when Colorado comes here,” Self said. “They got after him pretty good.”

KU once again got after the Buffs in handing them their 21st straight defeat at Allen Fieldhouse.

The Jayhawks, who led by 33 points — at 61-28 with 10:32 left — cleared the bench with six minutes to play. The onslaught probably made many forget the Richmond game.

“After that loss, we watched some tape and saw some of the things we didn’t do well,” Miles said after collecting seven assists, six points and four turnovers. “I think everybody took it upon themselves to do better. For example, J.R. did a tremendous job rebounding (eight) and playing defense, something he hadn’t been doing. Wayne got his rebounding edge back. He became a beast on the boards. We did a pretty good job today.”

Next up is Wednesday’s game at Kansas State. Tipoff is 8 p.m. at Bramlage Coliseum.