The exuberant Henderson's barrage combined with poor Wisconsin shooting to result in the upset. The Badgers hit just 15-of-59 from the field for 25.4 percent in the game.
The Rebels, who tied a school record with their 27th win against eight losses, will have a third-round game Sunday against 13th-seeded La Salle, which beat Kansas State 63-61 later Friday.
That result assures a double-digit-seeded team will reach the tournament's fourth round.
Sam Dekker hit a shot that put Wisconsin (23-12) up 36-30 with about 12 minutes to go but Henderson answered with two 3-point shots, setting off a 27-10 Rebels run the rest of the way. The Badgers managed just seven points over the final 9 minutes.
Henderson started slowly, with three points in the first half, but ended with a game-high 19 on 6-of-21 -- 3-of-12 from 3-point range -- shooting. Murphy Holloway, whose back-to-back shots erased the final Wisconsin lead, ended with 10 points.
Sam Dekker scored 14 points as the only Wisconsin player in double figures.
Aaron Carter is still in love with Hilary Duff
Millions of Getty images now available for free via embed tool