For the first time in more than eight years, Duke is not in The Associated Press Top 25.
The Blue Devils are 15-6 and have lost four of five, including two home games. They had been in every men's basketball poll since the preseason rankings of 2007-08, a streak of 167 weeks that was the fifth-longest run since the AP poll debuted in 1948-49. The record is UCLA's 221 straight polls from 1966 to 1980.
Oklahoma is 18-2 and was ranked No. 1 for the third straight week, receiving 45 first-place votes from the 65-member national media panel Monday. North Carolina is 19-2 and stayed second, with 20 No. 1 votes.
Villanova jumped three places to third and is followed in the top 10 by Maryland, Iowa, Xavier, Kansas, Texas A&M, Virginia and Michigan State.
No. 24 Dayton and No. 25 South Carolina are this week's newcomers, replacing Duke and Notre Dame.
Duke being unranked comes two weeks after the school's women's basketball team exited the AP Top 25 for the first time since November 1999.
ESPN Stats & Information and The Associated Press contributed to this report.