EVANSTON, Ill. (AP) -- Northwestern used an attacking defense -- and a weak schedule -- to jump out to its best start in 46 years.
But facing a ranked team for the first time this season, the Wildcats couldn't make the big stops against No. 23 Michigan State.
Javon Ringer rushed for 124 yards and two touchdowns as the Spartans cruised to a 37-20 win over previously unbeaten Northwestern on Saturday.
With a new coordinator in Mike Hankwitz, Northwestern's defense shined during the team's 5-0 start. But it couldn't overcome mistakes on offense and special teams that gave the Spartans great field position early.
Michigan State (6-1, 3-0 Big Ten) scored 17 straight points in the first quarter with the help of a pair of Northwestern turnovers, and never looked back.
"In the Big Ten, you can't spot a team 17 points and expect to win," Northwestern running back Tyrell Sutton said. "You can't sleep through the first quarter and the first half, expect to play one half of football and win."
The 5-foot-9, 202-pound Ringer had his fifth 100-yard game of the season and went over 1,000 yards for the second straight year. Ringer, who leads the nation with 14 rushing touchdowns, carried the ball 35 times.
"Great game, tough game," Michigan State coach Mark Dantonio said. "He got the tough yards. No fumbles, a big catch on a swing (pass). He's a complete football player."
Ringer gained only 3.5 yards per carry, more than a yard less than he's averaged this season.
"We knew they were going to do their best to try and bring people into the box," Ringer said. "All the credit goes to my offensive line. They continue to produce and continue to give me the holes that I need to be able to help move the ball down the field."
Both teams came in undefeated in the Big Ten. Michigan State left tied for first with Ohio State and Penn State, which played Saturday night at Wisconsin. The Spartans host Ohio State next.
"It will be an exciting atmosphere next week," Dantonio said.
Northwestern (5-1, 1-1) had been off to its best start since 1962, mostly by beating up on nonconference lightweights.
"We beat ourselves," Sutton said. "We had three turnovers and it was a three possession game. That's the tale of the game right there."
Sutton rushed 23 times for 139 yards and caught six passes for 44 yards.
Already leading 7-0 on Brian Hoyer's 3-yard scoring pass to Garrett Celek, the Spartans started their next two possessions in Northwestern territory thanks to turnovers. After Sherrick McManis fumbled a kickoff at his 25-yard line, Michigan State got a 26-yard field goal from Brett Swenson.
Michigan State safety Dan Fortener picked off C.J. Bacher on the Wildcats' next drive, returning it 21 yards to Northwestern's 34. Four plays later, Ringer bounced outside and scored from 13 yards out to make it 17-0 with 2:34 to play in the quarter.
"I don't think we were poised or focused to do our job," Northwestern coach Pat Fitzgerald said. "When a team doesn't play with poise and discipline, you get what you deserve, and that's what happened today."
Hoyer threw two short touchdown passes and was 14-of-20 for 169 yards.
"(Ringer) was getting a workload and they were bringing some guys up, so we had to take advantage of that," Hoyer said. "We came out, got hot quick and we were able to move the ball. We had great field position all day."
Sutton ripped off a career-high 66-yard run in Northwestern's first drive of the second half. Bacher then hit Rasheed Ward for a 6-yard touchdown pass to make it 24-14.
The Wildcats tried an onside kick, but were penalized for interference. That gave the Spartans the ball on the 32. Hoyer connected with Andrew Hawken on a 21-yard pass and Ringer ended the drive with a 1-yard touchdown run to keep Michigan State's lead safe.
"When you look at our special teams, when we said we had to have explosive plays out there and superior special teams play, we got that," Dantonio said. "That can be as big as anything. Three big returns, field goals, punts dropping in there, recovered a fumble. Those are all big things for us."
Swenson set a school record with the second of his three field goals. His 42-yard kick in the third was his 14th consecutive field goal, breaking Paul Edinger's 1998 record.
Bacher went 34-for-61 for 283 yards and two interceptions. He threw for a school-record 520 yards in last season's 48-41 overtime win over the Spartans. But Bacher couldn't duplicate that result.
Cornerback Johnny Adams picked Bacher off in the end zone with the Wildcats trailing 17-7 in the second quarter. The Spartans drove 80 yards in 3:03 to go up 24-7 just before the half ended.
"That was a big momentum swing in the game," Fitzgerald said.