"Nasty," Wildcats coach Pat Fitzgerald said with a hint of satisfaction. "Today was one of those great college football days. The guys handled it really well and had great focus, great energy."

That practice, ahead of Saturday's conference opener vs. the Gophers in Evanston, was another example for Fitzgerald of how his team's mentality has changed from a year ago, when Northwestern slumped to its second consecutive 5-7 finish. This season, the Wildcats' ability to move past obstacles is a big part of why they are 4-0 and the biggest surprise in the Big Ten West.

"I like the calm presence of the group," Fitzgerald said. "I think they've got poise, I think they've got solid focus."

It doesn't hurt that the Wildcats also have plenty of talent. Northwestern's scoring defense is ranked third nationally, allowing only 8.8 points per game. The Wildcats have blitzed more aggressively this season and have the best third-down stop percentage in college football.

And while the offense still is a work in progress, sophomore running back Justin Jackson has carried a big load while redshirt freshman quarterback Clayton Thorson has shown bursts of potential. Thorson has thrown three interceptions and managed only a 53.2 completion percentage, but he also has produced the kind of "wow" moments that have motivated the team to rally around him.

"You certainly wouldn't know Clayton is a freshman," offensive tackle Shane Mertz said. "Honestly. He might as well be a fifth-year senior for us. He's out there, he's leading the offense, he's talking to the [offensive] line, he's talking to receivers. I think he's done a phenomenal job this year."

Northwestern, unranked and picked to finish fifth in the Big Ten West before the season, has climbed to No. 16 in the Associated Press poll after stunning Stanford to open the season, routing Eastern Illinois, surviving a visit to Duke and then outlasting Ball State 24-19 last week.

But while the Big Ten West remains wide open, Northwestern's players know they have more to prove before they can be dubbed the new division favorite. Two years ago, they also began the year 4-0 before losing seven straight. The challenges this year, have hardly begun — after a Minnesota team that will test the Wildcats' fledgling offense, Northwestern will travel to Michigan, Nebraska and Wisconsin in the next two months. And as Fitzgerald pointed out Tuesday, the Wildcats have traditionally excelled in September, regardless of how the season ends.

The rest of the season will bring more than rainstorms.

"You understand your past, but you've got to flush it," defensive end Deonte Gibson said. "You've got to be ready to play right now. Everything that happened in prior years — it says that we'll struggle in October, but I don't believe so. We've just got to come ready to go tomorrow and the rest of this week and the rest of October and so forth."