The Tigers received 15 first-place votes, the most the defending national champions have received this season, and 1,446 points Sunday after beating Louisville 47-21 on the road. Alabama remains No. 1 with 45 first-place votes and 1,504 points.
Oklahoma slipped one spot to No. 3. The Sooners received the remaining first-place vote.
Clemson started the season at No. 5 because of some uncertainty at quarterback, where the Tigers had to replace Deshaun Watson, and other offensive positions. The Tigers have quickly showed they are still a legitimate threat to win a national title by smothering Auburn last week and then routing Lamar Jackson and Louisville on Saturday.
Clemson has been ranked no lower than sixth in the AP poll since Oct. 4, 2015, and has been ranked in the top five for 28 straight polls, the longest such active streak in the country. Alabama is second at 26 straight weeks.
Six ranked teams lost on Saturday, including five to unranked teams, shaking up the bottom of the Top 25.
No. 17 Mississippi State made the biggest move among the newcomers, entering the rankings for the first time this season at No. 17. The Bulldogs bashed LSU 37-7 in Starkville. Mississippi State had not been ranked since Nov. 22, 2015.
Joining Stanford in tumbling out of the rankings were: Kansas State, which lost 14-7 at Vanderbilt; Tennessee, which lost to Florida on a last-play touchdown pass; and UCLA, which lost 48-45 at Memphis.