I don't see how one could argue that the D failed against Illinois or even Wisconsin.
You hold a team to 2 or 3 scores, and you should win.
However, I do have concerns about the D overall.
I'd argue the D failed against BYU, Miami, Northwestern, and Purdue though.
Yeah, because the D gave it to the other team 4 times in our own territory.
Our offensive gameplan failed us in the Purdue game.
BYU game....Sure, but first game of the season in a brand new system, things were bound to break down.
Miami...Ok. Yeah. TA ultimately did throw the last YOLO pick though.
Purdue had 100 more yards against us than their season average. We gave up 55 points to them. You can't say that the D did not fail against Purdue.
Yes...the magical Purdue game lives on!