The theme was familiar, but the underlying causes were new.
Once again, an opponent tore through Notre Dame's defense, but a surprising second-half offensive surge ensured it got some rest in the second half. But in the first half, the Irish defense had trouble containing its opponent, a phenomenon not uncommon this season but often overshadowed by the team's offensive struggles.
The problem was simple. Stack the box to stop the run and Purdue senior quarterback Curtis Painter would slice through the thinned-out secondary with three and four-wide receiver sets. Play extra cornerbacks to take away the pass and senior running back Kory Sheets would take advantage of the resulting holes.
The Irish, with an undersized defensive line and slow linebackers, did neither. Painter completed 22-of-37 passes for 252 yards and two touchdowns and Sheets rushed 27 times for 141 yards and a touchdown.
At times, Notre Dame abandoned its new 3-4 scheme and played the nickel, with four linemen and two linebackers, to counter the spread offense. To do this, they moved sophomore John Ryan from outside linebacker to defensive end. Ryan said that the four-man line was hit-or-miss in its attempt to pressure Painter.
"I think sometimes we put good pressure on him and there were other times where we could have done a better job," he said.
Regardless of the change in scheme, Purdue's athleticism proved to be the main factor in the defense's problems. Their receivers, in particular senior Dorien Bryant who finished with eight catches for 82 yards, were too quick for the Irish secondary to cover one-on-one, a situation that the spread offense created often.
"That's part off the spread offense," Ryan said. "They spread you out and make you play in space. That was a big part of it, spreading us out."
Purdue's offensive linemen only allowed two sacks on 37 pass attempts.
"I feel like we didn't get enough pressure," defensive end Trevor Laws said. "At some points, we were back there, but I felt like overall we didn't do a good enough job of beating them to the space and disrupting."
The Boilermakers showed an example of this weakness in the first quarter. After a running play lost eight yards and a sack cost them another 11, Purdue faced a third-and-29 on their own 16-yard line. On the next play, Painter found junior receiver Greg Orton on the right sideline, a step ahead of sophomore cornerback Darrin Walls, for a 40-yard gain that gave Purdue a first down on Notre Dame's 43-yard line.
"We were playing good, I thought, first and second downs," Laws said. "A lot of times, we had them on third and longs, we weren't getting enough pressure up front and some guys in the back ends weren't making the plays."
When the Irish secondary was able to provide adequate coverage, Purdue switched to the run. Sheets had the middle of the field at his disposal and broke through the line for big gains. With the defense spread all over the field, no one remained to cover the middle, something Laws said was an important part of the spread offense.
"That's what they do. That's how they move the ball, they spread everybody out and find the middle," Laws said.
To further complicate matters, Purdue found ways to create mismatches and isolate Irish defenders, most often senior linebacker Maurice Crum Jr. and senior safety Tom Zbikowksi, in unfavorable single-coverage match-ups. Crum and Zbikowski found themselves covering the slot receiver or backs coming out of the backfield.
"They're just finding ways to get their playmakers the ball," Crum said. "They're just aligning them different places and just trying to create mismatches."
With 5:33 left in the game, Crum found himself covering senior receiver Dustin Keller. Keller got behind Crum and caught a 14-yard touchdown pass. Crum also lost track of Sheets on a corner route out of the backfield that would have been a touchdown if Painter hadn't overthrown the pass. Senior wide receiver Jake Standeford managed to shake Zbikowski's coverage in the second quarter and again was open for a big play had Painter put the pass on target.
Crum said the hardest part of defending against the spread offense was its unpredictability.
"The ball can go anywhere," he said. "That it's not just designed to go to one person, it can go anywhere."
