STATE COLLEGE, Pa. -- Marcus Allen knew exactly where to line up to change Penn State's season.

For two weeks, Allen said he performed "surgery" on game film of Ohio State, and in the week leading up to Saturday night's game, Penn State's field goal block unit practiced a specific strategy for attacking kicks off the foot of the Buckeyes' Tyler Durbin. On Durbin's first attempt in the second quarter, an eager Allen charged a gap, leaped and found himself just out of position to get the block.

In the fourth quarter, Allen got another chance, allowing him to learn from the first attempt and make an adjustment. The result was one of the most memorable plays in Penn State history, spurring a 24-21 upset of No. 2 Ohio State that stands as the Nittany Lions' most important win in years.

With 4:27 left and Penn State trailing by four, Ohio State settled for a field goal attempt to try to increase its lead to seven. Allen, a junior safety, moved slightly to the left on this kick, attacking the "B" gap, sure that Durbin's kick would come straight for him. Allen charged forward, jumped as high as he could and got his arm on it, deflecting it into open space.

"I jumped. Nobody touched me," Allen said, before rolling up his sleeve to reveal the spot where the ball hit his arm on a tattoo. "And I put my hands up and smacked it right into my koi fish. I still feel it. It's a great feeling."

Cornerback Grant Haley gathered the loose ball, sprinted downfield and stumbled as holder Cameron Johnston nearly caught him, but he found the end zone, stood up and raised his arms into the air as the white-out crowd Beaver Stadium roared around him, celebrating a 60-yard touchdown.

"When I seen Grant run, I knew nobody was catching him," Allen said with a laugh. "That boy runs a 4.3."

Allen's block and Haley's return gave Penn State a 24-21 lead over the Buckeyes that it would cling to for the final four minutes, sealing an improbable, unexpected signature win for James Franklin and the Nittany Lions while dealing a blow to the national championship hopes of the Buckeyes.

The blocked field goal return capped a 17-point fourth-quarter rally. A late second-quarter touchdown cut Ohio State's lead to 12-7 entering halftime, but the Buckeyes seemingly took control of the game in the third quarter. Curtis Samuel broke free for a 74-yard touchdown run that sucked the life out of the 107,280 fans in attendance. Penn State subsequently went three-and-out, and the punt snap sailed over Blake Gillikin's head and into the end zone, which resulted in a safety that put Ohio State ahead 21-7 halfway through the third quarter. For the second week in a row, it looked as if Ohio State would survive a tough prime-time test, seeking to extend its road winning streak to 21 games after escaping Wisconsin in overtime last Saturday.

The fourth quarter, however, belonged to Penn State, resulting in the most memorable night at Beaver Stadium in years, and certainly the team's biggest win since scandal rocked the university in 2011 and NCAA sanctions ravaged the football team afterward.

The Lions went on a five-play, 90-yard drive, then blocked an Ohio State punt, which set up a PSU field goal. J.T. Barrett and the Buckeyes proceeded to march down the field before stalling on the field on fourth-and-seven at the 28-yard line. Durbin trotted out for the 45-yard attempt, and Penn State made the defining play.

With its last chance, Ohio State picked up a pair of first downs and got the ball to the 42-yard line, needing a field goal to tie. But linebacker Jason Cabinda, who returned from a five-game injury absence, sacked Barrett for a loss of 13. The next play, on fourth-and-23 with the game on the line, Evan Schwan and Kevin Given wrapped Barrett up for another sack.

All Penn State had to do was kneel three times to set off one of the school's biggest celebrations ever.

White-clad students spilled onto the field. Players collapsed to the ground in joy and hugged and took pictures with random students passing by. A mass of fans joined the players in the corner of the end zone to sing the school's alma mater.

"Obviously these types of wins are important," Franklin said after the game. "To be honest with you, I don't really want to spend a whole lot of time thinking about the big picture right now. I just want to soak it all in. I just want to enjoy tonight, and I told these guys in the locker room I want them to go out and enjoy themselves tonight, and I want them to make good choices and all that kind of stuff, but before you leave the locker room, nights like this don't happen often. Savor it. Stay in this locker room, turn the music up and enjoy each other, because there's nothing outside that locker room that is better than what we've got going on in that locker room right now."

For years, Penn State has been mired in mediocrity, trying to regain its footing on the national stage while building its roster back to full strength. Franklin had not yet defeated a ranked team, and Penn State has not been ranked since 2011. This game, however, gave Penn State its first win over a top-two team since 1990 and its first win over the Buckeyes in Happy Valley since 2005.

Amid all the post-scandal, post-Paterno uncertainty, Penn State got the win that Franklin needed to build confidence in the direction of the program going forward.

"It's something that people dream about, playing in a white out, playing against the No. 2 team in the country, a game that put Penn State back on the map," Haley said. "We needed that signature win, and we did it tonight."

Saturday was not the end of the journey toward a return to consistent national prominence. But as Allen blocked the kick and Haley sprinted toward the end zone, a weight had been lifted, and a long-awaited marquee win could be celebrated. Allen moving a few inches to the left both blocked a kick and secured the football moment of a lifetime.