Jacob Charest threw for 185 yards and a touchdown after replacing Juice Williams, who left in the first quarter with an injured left ankle. Illinois (3-6, 2-5 Big Ten) led 28-7 at halftime.
Jon Hoese scored two fourth-quarter touchdowns for Minnesota (5-5, 3-4). Gophers linebacker Keanon Cooper blocked a punt that Ben Kuznia scooped up for a score to pull Minnesota within three points with 3 minutes to play.
The ensuing onside kick went out of bounds, and the Gophers couldn't overcome a dreadful first half from quarterback Adam Weber.
After throwing for 416 yards and five TDs in a breakout game against Michigan State last week, Weber completed 5 of 17 passes for 74 yards with a fumble and the interception returned for a score in the first half against Illinois. He finished 14 of 30 for 221 yards.
The blunders, and a furious pass rush, helped Illinois compensate for the loss of Williams.
It's been a long and difficult senior season for Williams, who has never been able to recapture the magic that helped him lead the Illini to the Rose Bowl during his sophomore year. He finally had a breakout game last week with 220 total yards in a 31-13 win over Michigan and looked sharp early against Minnesota.
He completed all five of his passes, including a 22-yard TD pass to Jeff Cumberland on the opening drive to get the Illini rolling. But he injured his left ankle and fumbled during a run later in the first quarter and watched the rest of the game on crutches from the sideline.
Weber probably wishes he could have joined him.
The Gophers quarterback also broke out of a season-long slump last week in a win over Michigan State.
He followed that with a brutal first half against Illinois, missing several wide-open receivers and taking too many sacks after not getting rid of the ball quickly enough, drawing boos from the home crowd.
Weber fumbled on a bad exchange with DeLeon Eskridge in Illinois territory and telegraphed a throw to Hoese near the sidelines in the first quarter.
Hawthorne, who chased down Michigan receiver Roy Roundtree and prevented a touchdown last week, read Weber's eyes and stepped in front of the pass. He returned the interception 44 yards for a score and a 14-0 lead going into the second quarter.
Minnesota cut the lead to 28-25 on Hoese's second score of the game. But Charest threw a 4-yard TD pass to Arrelious Benn on the next possession.