The loss puts Wisconsin (18-8, 8-5) in a tie with Illinois for third place in the Big Ten, one game behind Ohio State
, with three to play.
And the Badgers have Hachad to thank.
The senior guard shot 11-of-17 and hit two free throws with 47 seconds left that gave him 25 - two more than his previous high against Illinois last season.
Hachad drew a reaction from the Northwestern fans when he drove along the right side for a nice reverse layup to increase Northwestern's lead to 43-36 5:20 into the second half. That gave him 21 points - one more than his previous season-high.
Hachad's 22nd and 23rd points came on a dunk that made it 45-39 with about 12 minutes remaining. And the free throws near the end boosted Northwestern's lead 60-51.
Vedran Vukusic scored 13 points and tied the school record for 3-pointers for Northwestern (13-12, 5-8), which had lost two straight and four of six. The senior has 203 in his career - tying the mark set by Todd Leslie in the early 1990s - after hitting 1-of-3 from long range.
With a 45-40 lead midway through the second half, Northwestern scored seven straight and held on. Five of those points came on free throws, with Vukusic adding a tip-in that made it 52-40 with 7:22 left.
The Badgers went about 5:30 without a point and about 8:40 without a basket before Tucker hit a jumper to make it a 10-point game with 5:32 left. They got as close as five - 56-51 - after two free throws by Kammron Taylor with 1:22 left.
After scoring 19 in a loss to Ohio State on Saturday, Hachad picked up where he left off for Northwestern, hitting 7-of-11 shots in the first half. Averaging 11.3 points entering the game, he had 15 at the break as Northwestern took a 31-28 lead.
Hachad caught a full-court pass from Michael Jenkins for a layup, and after a Wisconsin turnover, he hit a 3 that made it 21-16 with 8:30 left in the first half. Hachad scored two baskets in an 11-second span that made it 31-26, Northwestern, with 1:25 left.
A jumper by Wisconsin's Alando Tucker accounted for the halftime score.