Godwin Igwebuike had three interceptions and Justin Jackson rushed for 162 yards, helping the resurgent Wildcats upset Melvin Gordon and No. 17 Wisconsin 20-14 on Saturday.
Trevor Siemian threw for a touchdown and also had a key block on Miles Shuler's 16-yard TD run as Northwestern (3-2, 2-0 Big Ten) earned its third consecutive win.
The Wildcats also had a nice day on special teams, with Jack Mitchell kicking two short field goals and punter Chris Gradone handing over poor field position to the Badgers for much of the afternoon.
Gordon had 27 carries for a career-high 259 yards and a touchdown, but Tanner McEvoy and Joel Stave combined for just 138 yards passing on a cold, damp afternoon at Ryan Field.
Wisconsin (3-2, 0-1) had scored at least 20 points in 17 consecutive games for the second-longest such streak in school history.