Smith netted 24 points and Siva added 20 for the Cardinals (6-1), who trailed most of the game but finally went ahead midway through the second half and then hung on as the Redbirds missed a pair of potential game-tying 3-pointers at the end.
Louisville rebounded after suffering its first defeat of the season Nov. 24 against Duke.
Illinois State (5-2) got 25 points from Tyler Brown and 20 from Jackie Carmichael in the loss.
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