Almost every week, Stanford coach David Shaw delegates a backup quarterback to the scout team in practice who can best simulate the upcoming opponent.
Not this week.
"We have to sign somebody," he joked.
Slowing down Mariota will be the top priority when sixth-ranked Stanford (7-1, 5-1 Pac-12) hosts No. 2 Oregon (8-0, 5-0) on Thursday night in a matchup of the winners of the past four conference championships.
In 21 starts, the Heisman Trophy hopeful has put up video game-like numbers against nearly every team he's faced. That is, except for Stanford.
The Cardinal handed Mariota the only loss of his career last season, 17-14 in overtime in Eugene. Stanford's victory ended then-No. 1 Oregon's three-year run as conference champion and dashed the Ducks' national championship dreams - not to mention Mariota's chances for college football's most prestigious award.
"If our guys use last year as a motivational factor to practice harder ... we'll take it," coach Mark Helfrich told Oregon's official website. "Any external motivation that was used to prepare, great."
Duplicating last season's performance might be even tougher for Stanford.
Mariota has thrown for 2,281 yards and 20 touchdowns and run for 587 yards and nine TDs this season. He's completing 64.0 percent of his passes and, perhaps most impressively, has not thrown an interception. The last time he was picked off was during last season's meeting with the Cardinal.
"I thought last year he was the best quarterback in the nation, and I feel the same way this year," Shaw said. "I don't care about stats. Stats don't mean anything. You watch the film, you see a kid that makes every throw. Every throw is accurate. Twenty touchdowns and no interceptions? Every ball is perfect, every ball is in stride, every ball there's no wobble on it. Everything's pretty.
"As a former receiver, you always appreciate that, a guy that just throws a pretty ball. And then when nobody's open, he just takes off and outruns everybody. You're designing a quarterback, that's what you want."
The secret to Stanford's success against Mariota remains somewhat of a mystery.
The Cardinal credit a physical, gap-plugging 3-4 scheme under defensive coordinator Derek Mason, who emphasizes the most basic fundamentals: tackling and discipline. Since losing 27-21 at Utah on Oct. 12, Stanford has shut down Brett Hundley and UCLA (10 points) and Sean Mannion and Oregon State (12 points) in back-to-back victories.
Now the Cardinal hope to make it three in a row with Mariota up next.
"He's a great player. He's going to make some plays. But we can't just let him take the ball, read what we're doing," said linebacker A.J. Tarpley, who intercepted Mariota last season. "We want to try and mix it up a little bit, whether that's attacking him, try to show something that looks like something but it's actually something else. We'll mix it up. We don't want them to get in their rhythm. Because once they do that, you can't stop them."
In the first 10 games before last season's meeting, the Ducks seemed unstoppable under Mariota. Oregon led the FBS with 54.8 points per game and never scored fewer than 42.
Mariota completed 21 of 37 passes for 207 yards, one touchdown and the one interception against Stanford. Besides a 77-yard run in the first quarter, Mariota netted only 12 yards rushing, often looking flustered under heavy pressure.
"I think a lot times we were hesitating a little bit and we were unsure of some of the fronts we were seeing," Mariota said. "That's the stuff we're really going to have to clean up."
One of the staples of Stanford's defense also is what Mariota avoids most: turnovers.
Stanford has forced a turnover in 33 straight games, the second-longest streak in the country. Being the first team to make Mariota throw an interception this season is a challenge Stanford knows will be difficult, but it's also one it will embrace.
"It's time," cornerback Alex Carter said, "for him to throw one."