Not to take anything away from MSU, but I'm torn over whether or not this is the biggest challenge of the season. Going up against Wake Forest earlier in the year gets serious consideration for a few reasons:
Wake is still regarded as better than MSU
High exposure Big Ten/ACC challenge game - which heavyweight is better?
Illinois was the underdog and had something to prove
Lack of time to "gel" under Coach Weber
On the other hand, MSU might be the biggest challenge because:
The game is at MSU (95-6 over last 7 yrs)
Rivals always bring their "A" game
MSU can pretty much kiss the Big Ten championship goodbye if they lose
Pressure of a perfect season for Illini
I still think Illinois will win. Oskee-wow-wow