CHAMPAIGN, Ill. -- Lori Bjork had 12 points and Chelsea Gordon and Erin Wigley added nine apiece to help Illinois upset No. 20 Michigan State 56-46 Thursday night.
Victoria Lucas-Perry led Michigan State (21-7, 12-3) with 14 points and six rebounds, while guard Mia Johnson added 11 points.
Illinois (18-9, 8-7 Big Ten) held a comfortable 31-21 lead going into halftime, but Michigan State's 6-foot-9 freshman center Allyssa DeHaan made a big push for the Spartans after the break, starting the second half with back-to-back baskets.
Bjork answered with a 3-pointer for the Illini and DeHaan hit another jumper to make it 34-27 Illinois less just over two minutes in. Both teams went scoreless from the field over the next 5:48, but Illinois still outscored the Spartans 6-0 over that time.
Illinois' shut down DeHaan, who averaged 12.3 points and 7.6 rebounds coming into Thursday's game. The Illini held her to a pair of free throws in the first 20 minutes, and eight points overall.
Bjork leads the nation with 27 straight games with at least two 3-pointers.
The win was Illinois' first against a ranked team since defeating then-No. 15 Oklahoma 86-75 on Dec. 18, 2005. Illinois has now beaten a ranked team for 13 consecutive seasons.