"Every UCLA-USC game, there is a guy who makes the difference," Donahue said. "Whether it's Gary Beban, Gaston Green, John Barnes, O.J. Simpson, Carson Palmer, Ricky Bell; whoever wins, there will be a guy."
It's the reason Donahue is picking UCLA over USC in the 84th football game between the schools Saturday at the Rose Bowl.
"We have had that guy the last two seasons," he said. "Brett Hundley will be the difference."
UCLA's hopes, and USC's fears, center on Hundley, the Bruins' junior quarterback. He had the Trojans' heads spinning last year when he passed for 208 yards and ran for 80 in a dominant, 35-14 UCLA victory.
It was Hundley's second win over USC in as many seasons as a starter. Another on Saturday would make him the fifth quarterback from either school to win three of the crosstown rivalry games.
But there is more at stake this season than personal achievement and a potential claim on a college football monopoly in Los Angeles.
UCLA, No. 9 in the College Football Playoff rankings, is 8-2 overall and 5-2 in Pac-12 Conference play. No. 19 USC is 7-3 and 6-2.
A win over USC, and another against Stanford next week, would earn UCLA a shot at No. 2 Oregon in the conference championship game. USC can earn a crack at the Ducks if it defeats the Bruins and Arizona State loses one of its two remaining games.
Hundley is the key to both scenarios. UCLA needs to spring him; USC needs to stop him.
"He has made plays throughout his career," USC defensive coordinator Justin Wilcox said. "You've got to do what you're best at, taking away what they do best, and that's how you play them."
Wilcox was at Washington last season and the Huskies limited Hundley to 15 yards rushing and 159 yards passing — but UCLA won easily, 41-31.
USC had less success two weeks later. Hundley's running tilted the game. He scored on runs of 12 and five yards. Both touchdowns came after USC had pulled to within seven points. He also had a 23-yard run that set up UCLA's last touchdown.
"We let our emotions get the best of us," USC defensive back Su'a Cravens said. "It's a rivalry game, things like that happen. This year, we just have to be cool, calm and collected and just go out and play our game."
Utah provided a blueprint for handling Hundley this season. The Utes shut off running lanes, applied pressure and locked down receivers in a 30-28 victory. Hundley was sacked 10 times.
Few teams can imitate the Utes' strong defensive front, but USC has the capability.
UCLA came into last season's game believing Hundley could hurt the Trojans on zone-read options, keepers or improvised scrambles.
"We saw some opportunities," UCLA offensive coordinator Noel Mazzone said. "He likes that part of the game plan. We really don't have very many calls like that. We usually have two or three. He keeps asking for more."
It's doubtful the game plan will change much this time.
"That's what I do," Hundley said. "It'd be nice to sit in the pocket and be Peyton Manning back there. Teams structure a game plan for what you're doing most. It's a game of cat and mouse."
Hundley has passed for 9,358 yards and a school-record 70 touchdowns in his career. But it's what Hundley does when he doesn't throw the ball that causes migraines for defensive coordinators.
In recent weeks, Pac-12 defenses have dared Hundley to run by dropping eight or nine players into coverage. And they have paid a price. Hundley has gained at least 89 yards rushing in four of the last five games. He has run for 564 yards and seven touchdowns this season — and 1,683 yards and 28 touchdowns in his UCLA career.
"A mobile quarterback offers you so much more flexibility," said UCLA Coach Jim Mora, who coached defense in the NFL. "It always caused me fits."
That element can change a team's pass coverage approach.
"If you're playing a lot of man-to man and backs are turned to him, that's not a good deal," Mora said. "So you see a little more zone."
Hundley said his mobility "can buy us time, allowing me to find windows to throw. If they're not there, I can take off."
That is what Wilcox schemed to stop this week.
"There's different ways to defend mobile quarterbacks, whether it's four-[man] fronts, whether it's three-[man] fronts, whether it's five-man pressures, whether it's maximum drops," Wilcox said.
Or all of the above.
Even then, there are no guarantees against Hundley.
"People have defended him well at times," Wilcox said, "and then he'll make a big play."
Staff writer Gary Klein contributed to this article.