Michigan State won each of its first six games of the season, four of them by double-digits. The Spartans beat the Notre Dame team that beat Kentucky at Kentucky. They beat Duke at Duke. On a surface level, at least, things were going perfectly.

But MSU hadn't been sharp.

The Spartans had slid from 11th at KenPom down to 20th despite winning every time out, a sign that they weren't performing well despite the fact that they were outscoring every opponent. So it was just a matter of time before the loss-column reflected as much. And that time came Sunday night in a big way.

Final score: Northwestern 79, Michigan State 65.

It represented the Spartans' first loss to Northwestern since January 2012. Michigan State allowed Chris Collins' team to shoot 52.9% from the field.

"One of the more inept performances of my 26 years," said Tom Izzo, who has been the head coach at Michigan State since 1995. "It's kind of a harsh statement. I'm blaming myself. I'm the one that has to have my team ready."

What I normally do when a highly ranked team takes its first bad loss of the season is implement a 10-spot auto-drop as a way to punish said team for losing without overreacting and dropping them completely out of the CBS Sports Top 25 And 1. But, in this case, a 10-spot auto-drop would only push Michigan State down from No. 5 to No. 15 — and No. 15 still seems too high. So I've decided to slot the Spartans at No. 17, one spot ahead of Duke. Next up for Michigan State is a possible bounce-back game with Wisconsin. If the Spartans don't win that, they'll be 0-2 in the Big Ten for the first time since the 2006-07 season.

Gonzaga remains No. 1 in Monday morning's updated CBS Sports Top 25 And 1 daily college basketball rankings. The undefeated Zags are scheduled to play Northwestern State on both Monday and Tuesday before traveling to Texas for Saturday's scheduled game with Virginia.

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Monday's Top 25 And 1 rankings

Biggest Movers
2 Rutgers
12 Michigan State
1 Gonzaga Jalen Suggs finished with 27 points, seven rebounds, four assists and three steals in Saturday's 99-88 victory over Iowa. The Zags' perfect record also includes wins over Kansas and West Virginia. --24-0
2 Baylor MaCio Teague finished with 23 points and 10 rebounds in Saturday's 100-69 victory over Kansas State. The Bears' perfect record also includes a double-digit win over Illinois. --21-1
3 Iowa The Hawkeyes missed 18 of the 22 3-pointers they attempted in Saturday's 99-88 loss to Gonzaga. Iowa's next scheduled game is Tuesday against Purdue. --20-7
4 Kansas Ochai Agbaji finished with 23 points and five rebounds in Thursday's 58-57 victory at Texas Tech. The Jayhawks' lone loss is a season-opening loss to top-ranked Gonzaga. --19-8
5 Tennessee Jaden Springer finished with 21 points, six rebounds and six assists in Friday's 103-49 victory over Tennessee Tech. The Vols' perfect record also includes wins over Colorado and Cincinnati. 117-7
6 Villanova Jeremiah Robinson-Earl finished with 25 points, seven rebounds and six assists in Saturday's 88-68 victory over Saint Joseph's. The Wildcats own wins over Texas and Arizona State with their lone loss coming in overtime to Virginia Tech. 116-5
7 W. Virginia Derek Culver finished with 18 points and 12 rebounds in Friday's 70-65 victory over Iowa State. The Mountaineers' lone loss is a single-digit loss to top-ranked Gonzaga. 118-8
8 Virginia Virginia's lone loss is a one-point loss to San Francisco. The Cavaliers have temporarily suspended basketball activities because of COVID-19 issues. 117-6
9 Houston Quentin Grimes finished with 27 points and 10 rebounds in Sunday's 88-55 victory over Alcorn State. The Cougars' perfect record also includes a double-digit win over Texas Tech. 121-3
10 Texas Greg Brown finished with 24 points and 14 rebounds in Sunday's 77-74 victory over Oklahoma State. The Longhorns' lone loss is a single-digit loss to Villanova. 117-7
11 Texas Tech The Red Raiders missed 17 of the 23 3-pointers they attempted in Thursday's 58-57 loss to Kansas. Texas Tech's two losses are to Kansas and Houston. 117-9
12 Wisconsin Micah Potter finished with 20 points and seven rebounds in Saturday's 85-48 victory over Louisville. The Badgers' lone loss is a final-second loss at Marquette. 116-11
13 Missouri Xavier Pinson finished with 17 points and five assists in Saturday's 81-78 victory over Illinois. Missouri's 5-0 record also includes a win over Oregon. 115-8
14 Creighton Christian Bishop finished with 19 points and five rebounds in Sunday's 76-74 OT victory at UConn. The Bluejays' will take a two-game winning streak into Wednesday's game with Xavier. 118-7
15 Rutgers Ron Harper Jr. finished with 28 points and nine rebounds in Sunday's 91-88 victory over Illinois. The Scarlet Knights' perfect record also includes wins over Syracuse and Maryland. 214-10
16 Illinois The Illini were outscored by 14 points at the free throw line in Sunday's 91-88 loss at Rutgers. Illinois' other two losses are to Baylor and Missouri. --20-6
17 Michigan St. The Spartans missed 23 of the 31 3-pointers they attempted in Sunday's 79-65 loss at Northwestern. Michigan State's next scheduled game is against Wisconsin on Christmas. 1215-11
18 Duke Matthew Hurt finished with 18 points and five rebounds in Wednesday's 75-65 victory at Notre Dame. The Blue Devils' two losses are both to teams ranked ahead of them in the Top 25 And 1. --11-11
19 N. Carolina Armando Bacot finished with 14 points and eight rebounds in Saturday's 75-63 victory over Kentucky. The Tar Heels' two losses are to Iowa and Texas. --16-9
20 Michigan Hunter Dickinson finished with 20 points and seven rebounds in Sunday's 62-58 victory over Penn State. The Wolverines' perfect record also features wins over Toledo and UCF. --19-3
21 Ohio St. Duane Washington Jr. finished with 14 points and five rebounds in Saturday's 77-70 victory over UCLA. The Buckeyes' next scheduled game is Wednesday against Rutgers. --18-8
22 LSU Javonte Smart finished with 25 points, six rebounds and five assists in Monday's 88-66 victory over Sam Houston State. The Tigers' lone loss is a single-digit loss at Saint Louis. 116-8
23 Oregon Chris Duarte finished with 21 points and four rebounds in Saturday's 80-41 victory over Portland. Oregon's lone loss is a single-digit loss to Missouri. 119-5
24 Arkansas Justin Smith finished with 22 points and 16 rebounds in Sunday's 87-76 victory over Oral Roberts. All seven of the Razorbacks' wins have come by double-digits. 121-5
25 Colorado Dallas Walton finished with 22 points in just 17 minutes in Sunday's 92-69 victory over Washington. The Buffaloes' lone loss is a single-digit loss to Tennessee. 120-7
26 Xavier Adam Kunkel hit a game-winning 3-pointer and finished 22 points in Sunday's 91-88 victory over Marquette. The Musketeers' perfect record also includes wins over Oklahoma and Cincinnati. NR13-7

IN: Xavier OUT: Saint Louis