If you call yourself a football fan, then you know about Saquon Barkley.

In Penn State’s first three games this season, the Swiss-army-knife running back has 655 total yards (rushing, receiving, and returning) and 5 touchdowns.

So how exactly does a team upset a rolling Penn State squad averaging 47 points per game and winning 12 of its last 13 contests?

Stopping Barkley, for starters, sure helps, but that’s a task easier screamed than accomplished.

Besides, there’s more to Penn State than its Heisman-hopeful tailback.

When the No. 4 Nittany Lions (3-0) clash with the Hawkeyes (3-0) at 6:30 p.m. Saturday, the Black and Gold will have their hands full, because for as much damage as Barkley can cause, he’s not the only weapon in Penn State’s arsenal.

“[Penn State has] good balance,” head coach Kirk Ferentz said. “Their receivers are all very talented. The tight end is a really big threat. They use him in a significant way, and I think the quarterback is really the guy that makes them go. He’s the center of everything.”

The supposed X-factor, quarterback Trace McSorley, is one of the nation’s top quarterbacks, slashing defenses on the ground while unloading bullets through the air.

RELATED: Iowa Notebook: Penn State’s many weapons

This season, McSorley has completed passes at a 67 percent rate, throwing for 753 yards and 9 touchdowns (184.1 rating), while running for 137 yards and two scores.

“[McSorley] does a great job being elusive, getting out of the pocket,” defensive end Parker Hesse said. “He can make a lot of plays that way. Being disruptive while containing him is an emphasis for us up front.”

Iowa knows just how big of a playmaker McSorley — and the rest of the Nittany Lion offense — can be, as was evident on the Hawkeyes’ plane ride home from Pennsylvania 2016 that seemed to take forever, Hesse said.

As a team that often relies heavily on the ground game, Iowa could only muster 30 rushing yards against a stifling Penn State front seven.

McSorley only needed 11 completions to rack up 240 passing yards and 2 touchdowns, and he added another 40 yards and a score in the running game.

Meanwhile, Barkley torched the Hawkeye defense with 211 total yards from scrimmage and 2 touchdowns.

“We were humiliated after that game,” Hesse said. “Human nature, you want to avenge that loss, but truthfully, you got to look at it objectively. These are two new teams.”

And that’s how Iowa is approaching this year’s matchup.

“Last year is last year,” cornerback Josh Jackson said.

The Hawkeyes, undefeated after nonconference play, have a history of performing well under the lights at Kinnick; in the past two seasons, Iowa is 4-0 in home games at night.

Linebacker Josey Jewell said Iowa possesses a certain hunger when it comes to night games, especially those it enters as an underdog.

For those doubting Iowa’s upset mentality, just ask Michigan. The No. 3 Wolverines walked out of Kinnick stadium with a 14-13 loss because of kicker Keith Duncan’s leg — his 33-yard field goal as time expired propelled the Hawkeyes to one of their biggest upsets in program history.

But, just as Jackson put it, last year is last year — this Iowa team is different, especially on offense.

Last season, Iowa had 11 passing touchdowns after eight games. This year, quarterback Nate Stanley has 10 touchdowns through three games — the most in a three-game stretch in the Ferentz era.