IOWA CITY, Iowa -- Juwan Johnson lined up on the right side of the line, with fellow Penn State receivers DaeSean Hamilton and DeAndre Thompkins on the left.

Tight end Mike Gesicki stood behind Johnson and drew Iowa linebacker Bo Bower out of the play. The Hawkeyes, on fourth-and-goal from the 7-yard line with four seconds to play and clinging to a four-point lead, sent six defenders toward Penn State quarterback Trace McSorley, including blitzing linebackers Ben Niemann and Josey Jewell.

OK, now rewind to early in the fourth quarter.

Johnson noticed that Iowa safety Miles Taylor was jumping to the outside in coverage.

So the sophomore wideout informed Josh Gattis, the Nittany Lions' receivers coach, that he could run a post route and beat Taylor deep. Johnson had caught hundreds of those balls, after all, over the summer and in practice already this season.

But from the 7-yard line? On fourth down, with the game and Penn State's unbeaten season in the balance?

"I said, 'I need a post. I think I can get him,'" Johnson said. "They finally called it the last play. It was just like another JUGS machine."

He came off the line fast. Too fast, in fact, requiring McSorley to put extra zip on the throw as the 6-foot-4 Johnson dashed to the outside -- taking Taylor with him -- and streaked inward toward the goal post.

"I wanted to put it high in a spot where only Juwan could get it and [where] it would fit through a tight window," McSorley said.

So it was a good thing that the junior QB delivered the ball especially firm. Because as Johnson flashed open in the end zone, Iowa's Amani Hooker ran in front of him, jumping high in a bid to deflect the pass. He just missed.

"My eyes just followed the ball the whole time," said left tackle Ryan Bates, who pushed Niemann off the edge to keep McSorley safe. "And then there was [Hooker]. He jumped up. I was like, 'Oh s---.' But it went over his head."

Johnson cradled it near the back of the end zone, the decisive touchdown as time expired in Penn State's 21-19 victory at Kinnick Stadium -- a thrilling finish to a game in which the Nittany Lions outgained Iowa 579-273 but needed a 12-play, 80-yard drive over the final 1:42 to escape with a win.

Penn State had a first-and-goal from the 10 before McSorley hit Gesicki for a 3-yard gain. Two incompletions followed, passes thrown to Thompkins and Hamilton.

The Nittany Lions called timeout before the final play. They needed to talk it through.

"It was clearly going to be the last play of the game," Penn State coach James Franklin said. "We felt like, with Juwan, we had a height advantage and could kind of slip him through the middle of the field.

"At that moment, the worst thing you can have is a lot of people talking. So we want to be calm and poised in those situations."

Johnson described the discussion on the sideline as something of a playground scenario.

"I guess you can say that," the receiver said. "We don't mind playing backyard football."

Offensive coordinator Joe Moorhead made the call. Johnson and Hamilton were the primary targets.

Left guard Steven Gonzalez and right tackle Will Fries blocked the Iowa defensive ends, both of whom had been disruptive.

Running back Saquon Barkley, who rushed for 214 yards on 28 carries and caught 12 passes for 94 yards, stayed in the pocket to pick up Jewell, the Hawkeyes' All-America candidate in the middle of the defense.

It all went according to script.

"Juwan ran a great route," McSorley said.

It was nothing he hadn't done hundreds of times in practice. And when he caught the ball?

"I kind of blanked out," Johnson said. "It was kind of like, 'I can't believe it happened.' But I know it can happen, I've been practicing it for so long. It's kind of like a dream."