But O'Brien wasn't done. Instead of going for the extra point to get Penn State within four, he decided to go for two. Michael Zordich rumbled up the middle into the end zone to get within 28-25.
Sparked by the fourth-down call, the Nittany Lions steamrolled over Northwestern from there in a 22-0 fourth quarter. For the year, Penn State leads the nation in fourth-down conversions (13) and attempts (20).
"We love it. It is an attitude kind of play," Zordich said about the fourth-down gambles. "We want touchdowns. That is what this offense is about ... We love it because it gets your mind right."
The defense loved it, too. Mauti's outside linebacker running mate, senior Gerald Hodges, gave his best performance of the year helping to shut down the Wildcats' potent attack to a season-low in total yards (247) a week after the Wildcats compiled a school-704 against Indiana.
The win was a huge confidence boost going into the bye week. The Nittany Lions will go through light workouts Monday-Wednesday, at least, and O'Brien will decide from there whether he'll run his team through any more drills.
There's still a lot upon which to improve, especially on special teams. A muffed punt by Jesse Della Valle at the Penn State 17 set up Northwestern's first score of the afternoon. Venric Mark's 75-yard punt return for a touchdown gave the Wildcats its short-lived 11-point lead late in the third quarter.
But the Nittany Lions rallied from adversity, like they have all season.
"Those things that happened over the summer and in the past are a lot bigger than football," O'Brien said. "These kids are just having fun playing football right now and going to school."
Follow Genaro Armas at http://twitter.com/GArmasAP