No. 17 Northwestern had arguably the most impressive résumé of anyone in the Big Ten, with key wins over Stanford and Duke in the first three weeks.

But that didn't mean that things would be easy for the Wildcats against Ball State in Week 4. Far from it. The Cardinals scored more points against Northwestern's defense -- which came into the day leading the FBS in points allowed -- than Stanford and Duke combined, and they left seven points on the board with two missed field goals and a botched extra point.

But all that mattered was that Northwestern held on for the 24-19 win on Saturday to improve to 4-0.

What the win means for Northwestern: The Wildcats completed a perfect nonconference season and should remain ranked in the top 20. Those are nice for bragging rights, but the real tests begin in Big Ten play, beginning next week against Minnesota. Pat Fitzgerald's team finally showed some spark on offense, with Clayton Thorson finding a good rhythm in the second half and Justin Jackson's skillful running leading the way toward nearly 550 total yards. The bad news is that the Wildcats got hit with a slew of injuries, with seven different players needing to leave the game. That included safety Godwin Igwebuike, defensive end Ifeadi Odenigbo and left tackle Geoff Mogus. It could prove to be a very costly win.

What the loss means for Ball State: Pete Lembo's team was hoping to beat a ranked opponent for the first time since 2012 (No. 23 Toledo). The Cardinals fell short but played very well. The 2-2 record is misleading, since it has included games against Texas A&M and Northwestern. Ball State won't get to ease into its MAC schedule, however, as Toledo and a road game at Northern Illinois are the first two contests on the agenda.

Player of the game: Split this one between Thorson and Jackson. Thorson has mostly been asked not to lose the game early this year, but the redshirt freshman quarterback showed something on Saturday, especially in the second half. He threw for 256 yards and three touchdowns. Jackson ran for a career-high 184 yards on 33 carries.

Uh, what?: On Ball State's next-to-last possession, Lembo elected to kick a field goal, trailing by eight points. Getting the lead from eight to five points wasn't all that helpful, and the Cardinals would end up with only one more offensive snap, deep in their own territory. The Cardinals played very well throughout the game. They deserved to have a chance to play for the tie.