Michigan had a chance to go up three, but Duncan Robinson split a pair of free throws with 14.3 seconds to play and left the door open for Northwestern.
Tre Demps got off jumper from the wing that misfired, but Alex Olah hit the put-back with 0.1 to play to tie the game at 60 and send it to overtime.
Michigan holding on late
Michigan trailed for the first time at 55-54, but got two free throws from Derrick Walton Jr. and a layup from Mark Donnal with 1:34 to play to go up 58-55
NW storming back
Michigan has made just two of its last eight shots and is now tied at 52 with Northwestern.