But with the Badgers trailing 10-6 at halftime, the senior linebacker knew what the first words out of Defensive Coordinator Dave Doeren's mouth would be in the locker room.
"He stressed that the seniors had to make plays and that we had to take care of the team," St. Jean said of the speech. "I was trying to be opportunistic and make (that) play."
St. Jean did make a play, and so did junior cornerback Antonio Fenelus, sophomore linebacker Mike Taylor and a chorus of other role players on the defense that helped stop Purdue's offensive engine in the second half, helping No.7 Wisconsin score 24 points off four vital turnovers to outlast Purdue, 34-14, in front of an announced crowd of 45,227 at Ross-Ade Stadium Saturday.
"We didn't come out there (right away) and do the best we could," said Fenelus, who was responsible for two turnovers Saturday, including a 36-yard interception for a touchdown in the fourth quarter. "We knew we had to play better … and it feels real good to go out there and make a play."
The Wisconsin (8-1, 4-1 Big Ten) offense wasn't the crisp unit that shredded the top ten defenses of Ohio State and Iowa in back-to-back weeks. Save a 57-yard drive in the final minute of the half, the offense managed just 69 first-half yards, complete with Scott Tolzien forcing a pass into traffic that was intercepted and Philip Welch badly missing a 40-yard field goal.
So with the Badgers needing a second-half spark, Purdue true freshman quarterback Sean Robinson gave it to the visitors in just three plays. Starting his first collegiate game, Robinson never saw St. Jean, who undercut an out route for a 14-yard interception return to the Purdue 18.
That play set up a seven-yard Tolzien-to-Jared Abbrederis 7-yard touchdown for a 13-10 Wisconsin lead.
"I just dropped back, read the quarterback and he took me right to the ball," said St. Jean, as the Badgers boosted their season turnover total to 11. "He's a young quarterback and we were just looking for opportunities. We just kept rolling with it."
While the Badgers would never relinquish the lead, Wisconsin still needed insurance. The Badgers got that in the form of sophomore Montee Ball stepping in when junior John Clay injured his right knee early in the third quarter. Ball ran for a career-high 127 yards and rushing scores of 31 and 15 yards.
The latter score was set up by an aggressive pass breakup by senior cornerback Niles Brinkley and the ball dropping into Taylor's hands, which he returned 26 yards to the Purdue 14.
"As long as I have been in this game, the more you emphasize (turnovers), they don't come and then they come in a flurry," UW Coach Bret Bielema said. "The kids really did a nice job. You've got to catch those passes and get them in the end zone, and they did that." Any thought of a late surge by Purdue was quieted when Fenelus picked off Robinson's high throw and went untouched for his first collegiate score with 8:31 left in the fourth.
"I knew the turnovers would come eventually, we just didn't know when," said Fenelus, who also led the team with nine tackles. "We just had to believe in each other and know that we could do it."
Facing the first of four straight spread offenses to finish the conference season, the Badgers struggled at tackling in space and staying assignment sound. The result was the Boilermakers (4-5, 2-3), who were trying to shake off back-to-back losses by a combined score of 93-10, finding some rhythm early.
Purdue marched 77 yards on its second drive to score only its second touchdown in the last nine quarters to take a 7-0 lead. The Boilers were primed for another touchdown drive when running back Dan Dierking broke a tackle at the UW 25, but the combination of Taylor and safety Aaron Henry ripped the ball out before Dierking's knee hit the grass.
The result was the ball scooting to Fenelus, who advanced the ball 48 yards to the Purdue 27, setting up a field goal.
That play seemed to spark Wisconsin, who were lucky to be trailing 10-6 at halftime after the Boilermakers picked apart the Badgers 3-3-5 defense to the tune of 173 yards and 6-for-9 on third down.
It could have been much worse if Wisconsin hadn't held the Boilermakers to a field goal on a 15-play drive that extended deep into UW territory. It was a series that was the start of the spark, as the Badgers limited Purdue to 130 yards on 37 plays (3.5 per play) and only 3-for-10 on third down.
"That says a lot about our defense and the perseverance we have," Wisconsin end J.J. Watt said. "Guys are willing to make plays and tough it out. A drive may not be going good, but we're going to continue to fight and play hard. Good things happen when you do that."