Scottie Lindsey scored five of his game-high 22 points in overtime and Northwestern trailed for much of the evening before pulling out a 72-68 victory over Illinois on Friday night in the Big Ten opener for both teams.
Vic Law added 16 points before fouling out in overtime and Bryant McIntosh had 14 points and six assists for Northwestern (5-3).
Leron Black led Illinois (6-2) with 15 points, whle Te'Jon Lucas and Mark Alstork had 14 points apiece.
Lindsey, the Wildcats' second-leading scorer this season, did not start after going 0 for 8 from the floor in Northwestern's 52-51 loss to Georgia Tech on Tuesday night.
His two free throws with 59 seconds left broke a 68-68 tie. Dererk Pardon had two key blocked shots in the final minute.
It was the earliest Big Ten game in Illinois' century-long history in the league. The Big Ten season was moved up because the league will hold its conference tournament a week early in order to stage it at Madison Square Garden in New York.