The sophomore QB threw for a career-high 391 yards and three touchdowns for the Illini (5-0, 1-0). All three TD passes went to A.J. Jenkins, who had 12 catches for a school-record 268 yards.
Scheelhaase had to engineer two comebacks to pull out the win over the Wildcats (2-2, 0-1).
First, Illinois scored 21 unanswered points after Northwestern took a 28-10 third-quarter lead. Then Scheelhaase scored the game-winning touchdown after a late touchdown run by Jacob Schmidt gave the Wildcats a 35-31 with just over a minute to play.
Wildcats quarterback Dan Persa played his first game in almost a year after tearing an Achilles tendon. He left late in the game but it wasn't immediately clear why.