But when the smoke cleared on a slightly soggy night, they were 5-0 and sure to burst into the top 10 of the national rankings.
Here's our breakdown of the game.
MAN OF THE HOUR: Who else but Derrick Williams, who scored three touchdowns in three different ways (receiving, rushing, kickoff return) and combined for 241 all-purpose yards? His best game yet.
CLOSE SECOND: Penn State quarterback Daryll Clark connected on 14 of 20 passes for 181 yards, two scores and no interceptions. Clark rushed for 50 yards, too. He looked like the best quarterback on the field.
CLOSE THIRD: Lion running back Evan Royster pounded out 139 yards on 19 carries.
TURNING POINT: Illini quarterback Juice Williams hit Arrelious Benn for a 33-yard TD in the first quarter on a play that was initially ruled incomplete but overturned by video replay. The play gave Illinois a 14-7 lead. Following the PAT and kickoff, Penn State took over at its own 19. Clark was hit and fumbled, and the Illini recovered deep in PSU territory. But another review showed Clark was down before fumbling and the call was overturned. The Lions were on the brink of falling into a 21-7 hole. Instead, they got the ball back, marched the field for a tying touchdown and gained momentum in the game.
SOLID STRATEGY: Penn State leaning heavily on Royster and the running game in the second half to chew clock and keep the pressure on the Illini defense.
NUMBERS GAME: After allowing 14 points in the first 12 minutes, the Lion defense allowed 10 points the rest of the night.
BUSINESS AS USUAL: Penn State's offensive line controlled the action when it mattered most.
SPECIAL DELIVERY: Place-kicker Kevin Kelly faked a 55-yard field goal attempt in the second quarter and instead punted. The ball was downed at the Illinois 7.
WHAT'S UP WITH?
Penn State continuing to have trouble holding onto the ball. Even with Clark's one miscue overturned, the Lions had two more fumbles Saturday, losing one.
Collin Wagner, being given a chance to handle kickoffs, booting his first try out of bounds. Not a good debut in that role this season. Kelly took over from there.
Knowledge Timmons, while serving as a blocker on PSU's punt return team, getting anywhere near the ball once it hits the ground. How many disasters and near-disasters can one man cause?
The Blue Royster Cult sign NOT showing up in front of the student section.
HIT SQUAD: Defensive end Maurice Evans sacked Juice Williams on a key third down last in the second quarter.
HIDDEN HERO: Backup safety Drew Astorino was only credited with two tackles. But one of them was behind the line on an option stuff. He also broke up a pass.
HEADS UP: Penn State senior linebacker Tyrell Sales sniffed out a trick play late in the third quarter, staying with Williams on an end-around that was clearly supposed to result in a pass back to the QB. Sales said PSU was beat on the play at Illinois last season and was ready for it this time around.
DID YOU NOTICE?
Penn State leading receiver Jordan Norwood did not play Saturday. He dressed but did not warm up. Norwood tweaked a hamstring in practice in the week leading up to the game and is expected to be back for next weeks game at Purdue.
Evans, fresh out of the doghouse, saw his first action of the game in a goal-line situation on Penn State's first defensive series. Fellow former suspendee Abe Koroma, a defensive tackle, saw his first action in the second quarter. Evans played extensively and finished with three tackles and the sack. Koroma had four tackles.
Penn State went with three defensive ends on the line (Josh Gaines moved to tackle) on an Illinois third and long late in the second quarter. Evans came through with the sack of Williams.
UNANSWERED QUESTION: Where will the Lions be rated now?