The Top 25 underwent a major overhaul last week after 14 ranked teams lost, including seven of the top 10.
Saturday turned into a February version of March Madness, with six top-10 teams losing, including Nos. 2 and 3 at home to unranked teams - a first in the 69-year history of the AP poll, according to ESPN Stats.
The day opened with Iowa State knocking off No. 3 Kansas 92-89 at Allen Fieldhouse. The Cyclones' victory, made possible by a school-record 18 3-pointers, bolstered their NCAA Tournament hopes and ended the Jayhawks' home winning streak at 51 games.
''They played with house money today,'' Kansas coach Bill Self said. ''I'm sure Steve would say the same thing. They came in here with a free mind and said, `Let's just let it go.'''
No. 2 Baylor was unable to finish off a big rally in a 56-54 loss to Kansas State in Waco. Bears star Johnathan Motley had two chances to tie in the closing seconds, but missed one and had the other blocked by D.J. Johnson.
Perhaps the biggest surprise came in the Pacific Northwest.
Not that No. 13 Oregon knocked off No. 5 Arizona. The way the Ducks did it.
Oregon jumped on the flat Wildcats early, building a 27-point lead in the first half behind a rash of 3-pointers. The Ducks hit 16 from behind the arc in the 85-58 victory, most since Mathew Knight Arena opened in 2011, and gave Arizona its worst loss under coach Sean Miller since 2009.
The win extended Oregon's nation-leading home win streak to 40 straight games, put an emphatic end to Arizona's 15-game winning streak and pulled the Ducks into a tie atop the Pac-12.
''I hope it's their best,'' Miller said. ''If they have another level above that, that's a bad thing for every team in the country. They played great and we didn't have any answers today.''
Top-ranked Gonzaga, No. 4 Villanova and No. 6 Louisville all won.
No. 8 Kentucky did not.
The Wildcats lost 88-66 to No. 24 Florida for their third loss in four games, a rare ugly stretch under coach John Calipari that may help spark a young team - or not.
''Sometimes you've got to hit bottom and maybe we have hit bottom, maybe we haven't hit bottom,'' Calipari said.
Oklahoma State kept the upset run going as another unranked team winning on the road, knocking off No. 7 West Virginia 82-75 in Morgantown.
Syracuse won as an unranked team, though did it at home, beating No. 9 Virginia 66-62 behind freshman Tyus Battle's 23 points.
The win was unofficially No. 1,000 for Orange coach Jim Boeheim, though the NCAA only counts it as 899 after stripping him of 101 wins in 2015 for punishment from a multiyear investigation into the school's athletic department.
No. 22 Creighton also lost to unranked Xavier - the Musketeers had been ranked most of the season - and No. 17 Maryland lost to No. 23 Purdue.
And to think, this is only the start of February. Wait until the madness of March.