It’s a terrible thing until it becomes a blessing. As awkward as it seemed that Stanford played USC in the second week of September — and it’s definitely something that shouldn’t happen — the Cardinal emerged from Saturday night’s game win a 17-3 win, an enhanced reputation and a performance that left the Trojans looking decidedly overmatched.

For Stanford fans who have followed this rivalry over the decades, complete with ample doses of heartbreak, that makes for one fine evening. Researchers had to go back to 1941 to find a less productive USC game against Stanford (a 13-0 win for coach Clark Shaughnessy’s defending Pacific Coast Conference champions).

The Top 25 pollsters are likely to be kind to Stanford in light of this performance, played under sublime, balmy conditions at Stanford Stadium. Preseason forecasts had the Cardinal relying heavily on running back Bryce Love, with a passing attack that would have to prove its worth. Love needed a full half to finally ignite his engine — and quarterback K.J. Costello dropped more hints that he’s ready to join the elite of Pac-12 quarterbacking.

Now that it’s done, Stanford can see the light. The conference record shows 1-0 and USC is out of the way. Next week should bring an easy win (at home against UC Davis) and leave the Cardinal unbeaten heading into a challenging two-game road swing through Oregon and Notre Dame.

It was crucial that Love show off his Heisman credentials, and in the wake of his 29-yard malaise against San Diego State, there were questions (something wrong with the man?) after USC held him to 40 yards on 11 first-half carries.

Then it happened. Early in the third quarter, Love got loose near the left sideline, turned on the speed and looked to be on his way to a touchdown, with only a single defender in his path and wide receiver JJ Arcega-Whiteside in perfect position to make a crushing block. Cornerback Greg Johnson made a tremendous play to bring down Love, but it was a 59-yard run and the type of explosive burst he executed last season as a matter of routine.

Costello is a dart thrower — and not the kind you see in Irish pubs. His accuracy comes with high-powered velocity, enough to find receivers in traffic at the exact moment the ball needs to arrive. He spread it around nicely, finding five different receivers, and his impact was less about numbers (16-for-27, 183 yards) than the visuals.

“They did a nice job getting some third-down pass plays,” USC head coach Clay Helton said, “and that one — third-and-long down the middle to the tight end (Kaden Smith, in the first quarter), that was just an unbelievable throw over the interior linebacker. We came in saying we couldn’t let JJ have the type of night he had in the first game, and we put together a good plan for that (Arcega-Whiteside caught four passes for 62 yards). But Costello gives them a more balanced offense.”

After a USC practice last week, linebacker Porter Gusin said the early arrival of this game would enable the Trojans to “be able to find out the identity of our team.” That will have to wait. The Trojans want no part of the identity they established Saturday night. And Helton is certain to come under fire for bypassing a 4th-and-2 punt at the Stanford 40 with less than two minutes remaining in the second quarter; quarterback JT Daniels fumbled (strip by Joey Alfieri, recovered by Bobby Okereke), and Stanford was able to drive for a touchdown and a 14-0 lead at the half.

As for Stanford’s identity, there’s no one thing — and that’s a dream scenario for head coach David Shaw. To his credit, he eased up on his pound-it-forever running game to showcase Costello’s burgeoning talent. The defensive line made big stops against USC’s running backs all night. And the secondary was particularly excellent, with potentially productive pass plays consistently broken up by Frank Buncom, Paulson Adebo, Alijah Holder and Malik Antoine, who provided the finish touches with a leaping interception at the goal line with 2:22 left and another pick in the waning seconds.

Everyone was anticipating a close look at Daniels, by all measures an especially promising freshman quarterback. He had a big game against Nevada-Las Vegas the previous Saturday, but he got a rude introduction to Pac-12 brutality when a blitzing Alfieri nailed him late in the first quarter, sending Daniels to the sideline with a bruised hand until early in the second quarter.

Daniels did uncork a beautifully delivered rainbow to wide receiver Michael Pittman in the third quarter, good for 45 yards down the left sideline, but in general, he was harried and flustered all night — and his vaunted fellow freshman, Amon-Ra St. Brown, caught just two passes in a zero-impact contribution.

As Helton addressed reporters afterward from a second-story enclave outside the stadium, the sounds of victory could be heard from the Stanford locker room below. There was thunderous cheering as the players shouted out the C-House chant and counted down the points, and for a while there, Helton could barely be heard. In a game that showed up much too soon, Stanford was right on time.

Bruce Jenkins is a San Francisco Chronicle columnist. Email: bjenkins@sfchronicle.com Twitter: @Bruce_Jenkins1