The Badgers scored the game's first six points and led 8-2 early but Northwestern rattled off a 34-11 run in the final 13:41 of the first half to take a 36-19 lead into halftime.
The Wildcats never allowed Wisconsin to get within single digits in the second half, leading by as many as 20 late in the game.
Wisconsin junior guard Devin Harris, who had scored 97 points in his last three outings, was held to 4 of 18 shooting and tallied a team-high 16. Only one other Badger, junior forward Zach Morley, reached double figures, with 15. Wisconsin's loss, coupled with Michigan State's 84-70 win over Ohio State moved the Spartans a half-game ahead in the Big Ten standings.
It was the second time in a month the Wildcats had knocked off a ranked team at home in convincing fashion—Jan. 14 Northwestern topped Illinois 70-60. The Wildcats are now 7-2 at home this season.
The Badgers struggled to master Northwestern's matchup zone defense, which limited UW to 29 percent shooting in the first half and 36 percent for the game. Wisconsin made just three field goals in the last 11 minutes of the first half, a span that included a 15-0 Wildcat run.
While the Badgers struggled to work their offense, Northwestern thrived, knocking down 51 percent of its shots, 59 percent in the first half. Vukusic led the way inside and junior forward Davor Duvancic drilling four 3-pointers.
Wisconsin pulled within 10 midway through the second half, but Northwestern rattled off eight points capped by a Duvancic 3-pointer to regain control.
It was the Wildcats' defense and transition offense, though, that made the difference—forcing 12 Wisconsin turnovers that helped Northwestern rack up 14 fast-break points compared to none for the Badgers.
Wisconsin could not establish a presence inside, finding only four shots for junior forward Mike Wilkinson, the team's second leading scorer, who was held to eight points. The Badgers shot just nine free throws, making eight, while Northwestern was 19-for-21.
Score by half
Wisconsin - (Field goals-Free throws-Points) - Devin Harris (4-6-16), Zach Morley (6-0-15), Mike Wilkinson (3-2-8), Andreas Helmigk (2-0-4), Ray Nixon (2-0-4), Dave Mader (1-0-2), Clayton Hanson (1-0-2). Totals: 19-8-51.
Northwestern - (Field goals-Free throws-Points) - Vedran Vukusic (5-7-18), Jitim Young (7-2-17), Davor Duvancic (4-0-12), Mohamed Hachad (4-0-9), T.J. Parker (0-8-8), Evan Seacat (1-2-5). Totals: 21-19-69.
Three point goals - Wisconsin 5 (Harris 2, Morley 3), Northwestern 8 (Duvancic 4, Vukusic, Young, Hachad, Seacat).
Rebounds - Wisconsin 29 (Harris 6), Northwestern 28 (Vukusic 7).
Assists - Wisconsin 17 (Harris 6), Northwestern 16 (Young, Duvancic 4) Turnovers - Wisconsin 12 (Harris 3), Northwestern 13 (three with 3).
Blocks - Wisconsin 1 (Nixon), Northwestern 4 (Hachad 2) Steals - Wisconsin 5 (Morley 3), Northwestern 8 (Young 4) Fouls - Wisconsin 16, Northwestern 14. Technical foul - Wisconsin Team.
Points - in the paint: Wisconsin 28, Northwestern 32 - Off turnovers: Wisconsin 15, Northwestern 15 - Fast break: Wisconsin 0, Northwestern 14 - Bench: Wisconsin 8, Northwestern 17 - Second chance: Wisconsin 5, Northwestern 6. Ties - 0. Lead changes - 3.