EVANSTON, Ill. — With nothing really to play for, and with the Big Ten championship game looming next weekend, Northwestern coach Pat Fitzgerald decided to pull many of his starters in the second half Saturday against rival Illinois.

Fitzgerald stuck with the plan in spite of unexpected tense moments down the stretch.

Clayton Thorson accounted for three touchdowns, Isaiah Browser rushed for 166 yards on 18 carries and No. 20 Northwestern beat Illinois 24-16 for its seventh straight Big Ten win.

Thorson completed 12 of 18 passes for 110 yards and two TDs. He also ran for a score, and Bowser posted his fourth 100-yard game of the season.

Neither was on the field as the game tightened late.

"You should have heard the headphones," Fitzgerald said of the communication with coordinators Mick McCall and Mike Hankwitz. "'Hey, I want ...' No. 'Hey, can I have ...' No. 'But what about ...' No.

"Sorry, I apologize to Mick and Hank. But to win our rivalry game with the amount of guys we had out — and what I didn't allow our coordinators to do — was awesome by our guys."

The Wildcats (8-4, 8-1, No. 19 in CFP) will face No. 10 Ohio State in the championship game in Indianapolis.

"We've got an unbelievable opportunity in front of us," Fitzgerald said. "I'm fired up to take the Purple to Indy. That's our goal every year, to win the Big Ten West. We've finally gotten over that hump, and now we have an opportunity, a 60-minute opportunity, to take this team to the Rose Bowl."

Illinois (4-8, 2-7) lost for the sixth time in seven games. AJ Bush Jr. completed 23 of 39 passes for 281 yards and a touchdown, and Ricky Smalling finished with seven receptions for 72 yards and a TD.

"Our guys fought hard from start to finish," Illini coach Lovie Smith said. "We left a lot of plays out there would like to have over, but the guys competed.

"We know we need to improve on a lot of things. But I like the way the guys came to work each day."

Northwestern retained the Land of Lincoln Trophy with its fourth straight win in the series, tying its longest winning streak.

"Beating our rival every year has been awesome," said Thorson, who started all four games.

With Illinois driving for a potential tying score, linebacker Paddy Fisher intercepted a Bush pass at the Northwestern 8-yard line with 3:34 remaining. The Wildcats, with TJ Green at quarterback and backups at running back, then ran out the clock.

The Illini have dropped 23 straight and 32 of 33 against teams ranked in the AP poll since beating No. 1 Ohio State in 2007.

Illinois moved the ball effectively — particularly through the air — in the first half, but only managed a pair of Chase McLaughlin field goals.

Northwestern was leading 7-6 when it scored on its final two possessions of the first half.

Thorson capped an 11-play, 75-yard drive with a 1-yard sneak. The Wildcats got the ball back with 1:47 left, and Thorson found Riley Lees for a 5-yard TD pass.

Jake Collins added a 25-yard field goal on the opening drive of the second half to make it 24-6.

FINISHING STRONG

Although the West Division title was clinched two weeks ago at Iowa, Thorson said the last two games were far from meaningless. "We never wanted to let off the gas," he said. "We never wanted to back into the Big Ten championship game."

NO CHANCE

Fitzgerald was asked if there was a chance Thorson might re-enter the game if Illinois had tied it. "One hundred percent, no," he said. "One million percent, no. Infinity, no."

THE TAKEAWAY

Illinois: The Illini are one of the youngest teams in college football, and they played like it. They had explosive plays throughout, but had to mostly settle for field goals because of mistakes at the wrong time. Smalling is elusive and routinely broke free in the secondary. But he struggled to catch the ball and had nearly as many drops as receptions.

Northwestern: Despite saying they wouldn't overlook Illinois because it was a rivalry game, the Wildcats clearly didn't have the same fire as in previous weeks. Bowser was shut down in the third quarter and Thorson was replaced by Green early in the fourth.

"I felt like we could win with the personnel we had in the game," Fitzgerald said.

UP NEXT

Illinois: Hosts Akron in the 2019 season opener on Aug. 31.

Northwestern: The Wildcats have dropped six straight against Ohio State and have beaten the Buckeyes just once since 1972.