As the going demands more toughness, can USC get it going?

USC’s game against Stanford on Saturday night is not about revenge for last year’s beat-down at the Coliseum.

The two-point conversion that riled Pete Carroll?

That’s history, as is Carroll.

No, with Lane Kiffin’s embattled Trojans coming off what might have been a program-shifting loss to Washington, here’s the deal:

This game is about toughness.

Specifically, whether USC’s got enough.

Trojans coaches had billed the season as a “13-round heavyweight fight,” posting motivational fliers throughout Heritage Hall after each “round.” The message included a count of major college football’s unbeaten teams.

USC, unimpressive in four victories, was KO’d from those ranks last week.

Now Kiffin and the Trojans must get up off the canvas — or watch their season, and possibly the future of the program, go sideways.

Are they tough enough?

Stanford offers an ideal opportunity to find out.

Smash- mouth. Punch in the gut. However you want to describe it, Cardinal Coach Jim Harbaugh has molded his bruising team in his image.

Example: Harbaugh spoke this week of a Cardinal player’s chasing down an Oregon speedster and making “a physical tackle” to prevent a touchdown on a fumble return.

The Stanford player?

Quarterback Andrew Luck.

“That was indicative of how he played the game that night and this year,” Harbaugh said.

Kiffin has noticed.

USC’s first-year coach called Saturday’s matchup “a physical test-of-will game.” He waxed poetic all week about Stanford’s bruising style and discipline, repeating like a mantra the qualities he wants his staggering Trojans to emulate.

Kiffin, via Twitter, even quoted that noted Xs and O’s guy from China: “Our greatest glory is not in never falling, but in rising every time we fall,” Kiffin wrote, citing Confucius.

After Wednesday’s practice, perhaps the Trojans’ most physical since training camp, linebacker Chris Galippo said he would forever remember last year’s embarrassing 55-21 loss to Stanford at the Coliseum — and the Cardinal’s unrelenting rushing attack.

In the wake of the loss to Washington, Galippo said, the Trojans are “kind of just on the ledge,” ready to leap.

Whether it’s up to the next level or down into the abyss of another disappointing season remains to be seen.

A trip to Stanford Stadium, Galippo said, offers the Trojans an opportunity to fight their way out in a hostile environment.

“This is one of those weeks where you kind of go, ‘This is it,’” he said. “You either put up or shut up.”

Harbaugh seems to coach by that credo every game.

Last November, he went for the now-famous two-point conversion against the Trojans when the Cardinal was ahead 48-21 in the fourth quarter. “Nothing personal,” he said later.

This season, with his team leading Wake Forest by 34 points late in the first half, Harbaugh called time out to try to ice the Demon Deacons’ field-goal kicker. Later, he challenged an officials’ call with the Cardinal leading by 44 points.

Now Stanford is coming off the wrong side of a beating, a 52-31 loss to third-ranked Oregon.

So it might not be the best time to meet an opponent that USC defensive tackle Jurrell Casey remembers “out-physicaling us up front and running the ball down our throat” last season.

“I’m pretty sure they’re going to come out and try to do it again this year,” he said.

Are the Trojans, as 10-point underdogs, tough enough to withstand the assault?

If not, it could be a slaughter at the Farm.

If so, it could be a turning point for Kiffin and his sanctions-strapped program.

Oscar Lua was a gritty middle linebacker and special teams standout for the Trojans from 2002 to 2006. He was there when the program turned under Carroll and USC won five of what would become seven straight Pacific 10 Conference championships and nearly won three consecutive national titles.

“We were so sure of ourselves, of what we were about,” Lua said of the defense. “One heartbeat, that was our motto, and we held to that.”

These Trojans are still trying to find an identity.

The spark, Lua said, could come from the kickoff team “lighting up the stands with a hit and getting the whole thing going. All it takes is one guy getting in there and firing up your teammates.”

One guy to show he’s tough enough.

“There are moments and games when you find out who you are,” he said. “This is one of them for our boys.”

gary.klein@latimes.com

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