Isaiah Bowser set the tone for the drive by running over Ohio State safety Brendon White on the first play, and quarterback Clayton Thorson capped it with an 18-yard scramble for a touchdown.
That was a sign of what was to come as the Wildcats dominated most of the third quarter.
After the Buckeyes went three-and-out, Northwestern went on the march again. This time the Wildcats needed 11 plays to go 85 yards for a touchdown drive that concluded with a 2-yard pass from Thorson to Cameron Green.
The Buckeyes found themselves late in the quarter, though, as Haskins hooked up with Chris Olave from 29 yards out to restore a 10-point cushion with 1:21 left in the stanza.
Ohio State looked to add to the lead early in the fourth quarter, but Blake Haubeil’s 27-yard field goal was blocked.
The Wildcats took the ball from the 20 and drove to the Ohio State 4 before stalling out and having to settle for a 21-yard field goal by Charlie Kuhbander to make it 31-24 OSU with 10:34 left.
The Buckeyes needed less than two minutes to answer as Haskins found Johnnie Dixon in the end zone for a 9-yard touchdown pass. That was set up by a 63-yard connection between Haskins and Dixon.
Haskins finished the night five minutes later with a 17-yard touchdown pass to J.K. Dobbins that put the game well out of reach.
Ohio State leads Northwestern 24-7 at halftime of the Big Ten championship game.
Ohio State struck first as Dwayne Haskins eluded a potential sack, scrambled and found Terry McLaurin in the end zone for a 16-yard touchdown with 10:31 left in the first quarter.
That capped a 10-play, 77-yard drive that saw the Buckeyes convert a pair of third downs.
The Wildcats struck back when John Moten IV broke through the right side of the line and sprinted down the sideline 77 yards for a touchdown with 6:27 left in the first quarter.
Springboro’s Charlie Kuhbander followed with a PAT kick to tie the score at 7.
The Buckeyes went back in front on J.K. Dobbins’ 2-yard run with 3:29 left in the first quarter. That capped an eight-play, 65-yard drive.
Midway through the second quarter, Ohio State had a chance to open some distance but had to settle for a 42-yard field goal after the Buckeyes got the ball near midfield following a Clayton Thorson fumble forced by Chase Young.
Ohio State struck one more time late in the second quarter when Haskins hurled a rainbow for McLaurin, who got behind the secondary for a 42-yard score.
Haskins completed 18 of 22 passes for 249 yards and two touchdowns in the first half.
His top target was Parris Campbell, who caught six passes for 79 yards while McLaurin had three catches for 78 yards and the TDs.
Almost half of Northwestern’s total yards (160) came on Moten’s run.
Ohio State and Northwestern are set to play for the Big Ten championship at 8:17 tonight at Lucas Oil Stadium.
The Buckeyes are looking to repeat as champions while the Wildcats are seeking their first conference title since 2000.
>>READ MORE: 5 things to know about the championship game
Ohio State has not played yet, but there has already been bad news for the Buckeyes.
Oklahoma topped Texas 39-27 in the Big 12 championship Saturday afternoon, likely putting the fifth-ranked Sooners in prime position to get into the College Football Playoff if No. 1 Alabama beats No. 4 Georgia in the SEC championship game.
Texas, coaches by former Ohio State offensive coordinator Tom Herman, led for most of the first half but couldn’t sustain offensive success late.
The beleaguered Sooners defense made two big plays in the fourth quarter, extending their lead to 32-27 with a safety then coming up with a game-clinching interception on Texas’ last drive.