Duke was a unanimous No. 1 in the AP college basketball poll for the second straight week Monday, while three teams fell from the Top 25.
The Blue Devils (8-0), who beat Temple and Michigan last week, received all 72 first-place votes and 1,800 points from the national media panel.
Missouri, Maryland and Kansas held second through fourth and Florida moved up one spot to round out the first five.
Arizona and Virginia each moved up one place to sixth and seventh, and were followed in the Top Ten by Oklahoma State, Kentucky and Illinois.
Only one of the three newcomers to the rankings is in for the first time this season.
Gonzaga (7-2), which has been in the NCAA tournament round of 16 each of the last three seasons, moved in at No. 25, the Zags' first appearance in the poll since being ranked for the first seven weeks of the 1999-2000 season.
Indiana (6-2), which was out of the poll the last two weeks after getting as high as No. 20, moved back in at No. 21, and Oklahoma (5-1), which was 25th in the preseason poll then fell out, returned to the rankings at 24th.
Boston College moved up two places to lead the Second Ten and was followed by Stanford, Syracuse, Marquette, Iowa, Saint Joseph's, UCLA, Georgetown, Wake Forest and Ball State.
The last five ranked teams were Indiana, Alabama, Michigan State, Oklahoma and Gonzaga.
Indiana's return to the rankings followed wins over instate rivals Notre Dame and Ball State.
Oklahoma beat St. Bonaventure and Louisiana Tech last week to stretch its winning streak to four games after losing to Michigan State in the second round of the Preseason NIT.
Gonzaga returned to the Top 25 following victories last week over Eastern Washington and Fresno State. The Bulldogs' losses have been to Illinois in the season opener and to Marquette in the championship game of the Great Alaska Shootout.