Mississippi 57, Wisconsin 46: Marshall Henderson scored 17 of his 19 points in the second half as the 12-seeded Rebels upset the Badgers in the second round of the NCAA Tournament at Kansas City, Mo.Murphy Holloway collected 10 points and nine rebounds and Reginald Buckner added nine and 12 for Mississippi (27-8), which won its opening game for the first time since the 2001 squad reached the Sweet 16. The Rebels will play La Salle in Sunday's third round.Sam Dekker scored 14 points off the bench as Wisconsin (23-12) had its six-year streak of opening round wins in the Tournament come to an end. The Badgers shot 25.4 percent, including 7-of-30 from 3-point range. Henderson missed 12 of his first 13 shots before burying his first 3-pointer to pull the Rebels within 36-33 with 11:22 left. He knocked down another from beyond the arc less than two minutes later to tie it and totaled 13 points during a 20-8 burst that left Mississippi with a 50-44 lead with 2:48 to play.Wisconsin missed six straight 3-point attempts over the next 83 seconds and Henderson closed it out, breaking free for a layup and burying two free throws with 39 seconds to play.GAME NOTEBOOK: The Badgers did not have a starter make more than two field goals and shot 22.2 percent after the break. … Mississippi G Jarvis Summers and Henderson combined to go 7-of-7 from the free throw line. The rest of the Rebels were 3-of-9. … Wisconsin last suffered an opening loss against Arizona in 2006. The Badgers had won at least one game in the Tournament in 10 of their previous 11 trips.