The Wildcats had been ranked No. 2 seven times — last time the final poll of last season — but had never made that one step up.
"There's still a lot of basketball left to be played and handling this will be another challenge for our team," Villanova coach Jay Wright said. "We look forward to it."
There are eight schools to have held the top spot for one — and only one — week. The most recent was Tennessee in 2007-08 and Wisconsin the year before.
UCLA is the all-time leader with 134 weeks at the top — the last in 2006-07 — and Duke is next at 127, the last in 2012-13.
The only other schools to have spent over 100 weeks at the top are Kentucky (115) and North Carolina (113).
As far as the most weeks spent at No. 2 without reaching No. 1 is this week's No. 2, Maryland. The Terrapins are in the runner-up spot for the 26th time. The only other school in double figures is Purdue at 10 weeks. Dayton and Saint Bonaventure, both at seven weeks, were the only other schools above Villanova on the list.
WHO'S No. 1: Villanova becomes the sixth school to hold the No. 1 spot this season, just one off the record.
North Carolina and Kentucky were both No. 1 for two weeks. Michigan State held it for three, Kansas two and Oklahoma three.
There were seven teams ranked No. 1 in 1982-83: Houston, Indiana, Memphis, UNLV, North Carolina, UCLA, Virginia.
There have been six No. 1s in five other seasons, the last in 2008-09: North Carolina, Pittsburgh, Wake Forest, Duke, Connecticut, Louisville.
NEW GUY: Texas moves in at No. 24, the Longhorns' first ranking since last season. They were ranked for the first 13 weeks of 2014-15, reaching as high as sixth. This is their first ranking under first-year coach Shaka Smart. Texas (16-7) comes in on a four-game winning streak and the Longhorns have won seven of eight with the only loss at Kansas.
Southern California (18-5) rejoins the poll after being out two weeks. The Trojans return on a three-game winning streak and they have won six of eight, the losses on the same weekend to Oregon and Oregon State. Southern Cal had last been ranked in 2008-09.
TOUGH TRIP: Indiana and South Carolina were the two teams to drop out this week and both are having pretty impressive seasons.
Indiana (19-5) was ranked 22nd and the Hoosiers fell out after a 68-63 loss at Penn State. They are one game out of first place in the Big Ten and they are the only school in the top five teams in the conference not to be ranked. Indiana had been ranked the last three weeks.
South Carolina (20-3) lost 69-56 at Georgia early in the week and rebounded with an 81-78 win at then-No. 8 Texas A&M. It wasn't enough to keep the Gamecocks, who are tied for second in the Southeastern Conference, from falling out after a one-week run.
CONFERENCE CALL: Texas moving into the Top 25 gives the Big 12 the top spot among the conferences with six teams. The Big 12 had been tied with the Big Ten but Indiana dropped out.
The Big Ten and Atlantic Coast Conference both have four teams while the Big East and Pac-12 have three each.
DOUBLE-RANKED: Clear your schedule. Put the phone on airplane mode. There is no way to miss the rematch of the season's best game. On Saturday, No. 6 Kansas is at No. 3 Oklahoma. The first time they met, in Allen Fieldhouse, Kansas prevailed 109-106 in triple overtime.
Oklahoma and Kansas each have another game against a ranked team before they meet. The Sooners host No. 24 Texas on Monday and Kansas hosts No. 10 West Virginia on Tuesday.
Texas' first week in the poll will see the Longhorns face Oklahoma as well as visiting No. 14 Iowa State on Saturday.
In other double-ranked games, No. 8 Michigan State visits No. 18 Purdue on Tuesday and No. 23 Southern Cal is at No. 17 Arizona on Sunday.