Tracy Abrams scored 12 points, leading Illinois to a 53-46 win over No. 18 Michigan State on Saturday.
The Fighting Illini (17-12, 6-10 Big Ten) have three straight victories for the first time since winning four in a row from Dec. 21 to Jan. 4. That successful stretch included a win over then-No. 23 Missouri.
The Spartans (22-7, 11-5) have dropped two straight and six of their last 10 games. They were full strength for the first time in nearly two months, but simply weren't good enough to beat a streaking team that seemed more inspired.
Branden Dawson returned from a broken hand and played for the first time since Jan. 21, when he helped Michigan State beat Indiana to improve to 18-1 overall and 7-0 in conference.
Michigan State's Gary Harris had 19 points, and didn't get much help from his teammates.
The Spartans scored a season-low 46 points -- five fewer than they had two weeks ago in a nine-point loss to Nebraska. They made 39 percent of their shots and had only one player with more than seven points.
Adreian Payne, who averages 16-plus points, had just four points. Freshman forward Gavin Schilling matched his career high with seven points.
Illinois, meanwhile, had a trio of double-digit scorers and made nearly 48 percent of its shots. Malcom Hill and Rayvonte Rice each had 10 points.
The Illini took advantage of a call that went their way and enraged Michigan State coach Tom Izzo -- and appeared to rattle his players.
Harris had a steal and a layup waved off because the officials decided a shot-clock violation happened before the turnover.
Instead of the basket pulling the Spartans within a point, its deficit stayed at three and quickly grew to six points.
The Illini won at Michigan State for the first time since March 3, 2006, and beat a ranked Big Ten team for the first time since Feb. 10, 2013, when they knocked off No. 18 Minnesota.