New York Kansas University's victory over defending national champion and top-ranked Florida meant a jump of five spots in the Associated Press poll for the Jayhawks.
KU (5-1) moved from 10th to fifth in the rankings, while Florida dropped three slots to fourth.
UCLA combined its championship at the Maui Invitational with losses by Florida and No. 2 North Carolina to vault from fifth to the top spot. It is UCLA's 129th poll with a No. 1 ranking, 19 more than runner-up Duke.
The last time the Bruins were No. 1 was the final poll of the 1994-95 season, when they went on to win their record 11th national title.
North Carolina, which was second to the Gators in all three polls this season, lost 82-74 to Gonzaga in the semifinals of the NIT Season Tip-Off in New York on Wednesday, and fell to seventh.
Pittsburgh (6-0) and Ohio State (6-0) each moved up one place to second and third. UCLA received 36 first-place votes and 1,727 points from the 72-member national media panel. Pittsburgh, which matched the highest ranking in school history, was No. 1 on 18 ballots with 1,666 points. Ohio State had 15 first-place votes and Florida received three.
Kansas was fifth followed by Alabama, North Carolina, Marquette, Texas A&M and LSU.
Half the top 10 lost last week, and five other ranked teams also went down, including Kentucky and Tennessee twice each.
In addition to Florida and North Carolina losing, No. 6 LSU was beaten at home by then-No. 24 Wichita State while No. 7 Wisconsin fell to Missouri State and No. 9 Duke was beaten by then-No. 13 Marquette.
Butler and Gonzaga, which upset ranked teams to reach the championship game of the NIT Season Tip-Off, and Virginia all moved into the Top 25 for the first time this season.
The two losses cost Kentucky and Tennessee their places in the poll while Boston College also dropped out.
Duke was 11th and was followed by Wisconsin, Washington, Memphis, Syracuse, Arizona, Wichita State, Georgetown, Butler and Connecticut.
The last five ranked teams were Georgia Tech, Gonzaga, Maryland, Nevada and Virginia.
In the Bruins' first week back on top they will play twice at home - today against Long Beach State and Sunday against UC Riverside.
Butler (7-0) jumped in at No. 19 after beating Tennessee and Gonzaga at Madison Square Garden to win the NIT Season Tip-Off and then beating Kent State in double overtime Saturday.
The Bulldogs were last ranked for three weeks in 2001-02, reaching as high as 20th. The only other time they were ranked was for eight weeks in 1948-49, the first season there was a poll, when Butler reached as high as No. 11.
No. 22 Gonzaga is no stranger to the Top 25. The Bulldogs (6-1) were ranked all but one week of the last three seasons. They were in the top 10 throughout 2005-06 and were as high as No. 4. Despite losing Adam Morrison a year early to the NBA, Gonzaga remained a major factor on the national scene by beating North Carolina, 82-74, in the NIT semifinal.
Virginia (4-0) beat North Carolina-Asheville and Maryland-Eastern Shore last week to cap a season-opening homestand in its new John Paul Jones Arena. The Cavaliers were last ranked during a five-week stretch in 2004-05.
Kentucky (3-2) lost to UCLA and Memphis in the Maui Invitational last week while Tennessee (4-2) fell to Butler and North Carolina in the NIT.
Boston College (2-2), which fell at home to Vermont at home Nov. 13, lost at Providence last week.