Steve Vasturia and Demetrius Jackson scored 21 points apiece to bring Notre Dame back from an 8-point halftime deficit to beat Illinois 84-79 on Wednesday.
The Fighting Irish (5-2) spoiled the reopening of Illinois' recently renovated State Farm Center with the win.
Notre Dame had lost two of three coming into the game and fallen out of the Associated Press Top 25.
But a 3-pointer from Vasturia with 1:54 to play put Notre Dame up 72-62.
Illinois rode tough defense and the energy of the first night back in its campus arena to a 41-33 halftime lead.
But the Illini (3-5) went cold from the floor in the second half.
Malcolm Hill led Illinois with 19 points, while Kendrick Nunn had 13 points and seven rebounds.
Zach Auguste added 16 points with 14 rebounds for Notre Dame.