Script, flipped.

The Rams finally beat the San Francisco 49ers in a meaningful regular-season game.

Kyren Williams flipped too.

If you haven’t seen it, you soon will. It’s an Instagram instant classic, a bit of in-your-Facebook flair. The Rams running back ran what’s called an arrow route through the middle of the 49ers defense, caught a beautifully timed pass from Matthew Stafford — one that required the precision of throwing into an open car window passing on the freeway — and punctuated the 15-yard touchdown with an impromptu front flip into the end zone.

Williams wound up on his tush instead of his toes.

“He didn’t stick the landing,” needled rookie running back Blake Corum from the locker next door. “I teased him about that.”

That’s about the only valid critique of Williams in the 27-24 stunner, an ultra-rare upset of the NFC West bullies by the Bay. He scored all three touchdowns, adding a pair of scoring runs to his gem of a catch and carry.

“We haven’t gotten to use him as a pass catcher enough,” Rams coach Sean McVay said. “I thought he did a great job of breaking off man coverage and then be able to have the swag to flip in was pretty cool.”

The Rams were in a desperate spot, in danger of dropping to 0-3 and losing a second division game on the heels of a dispiriting blowout defeat at Arizona.

“Obviously there was a sense of urgency to this week about our preparation and the mentality of what we were going to do and how we were going to play,” Williams said. “But I think it was something that was kind of unspoken, something that we knew we had to do. An 0-3 start is not good. We prepared this week to make sure that didn’t happen.”

The game was a battle of the backups on both sides, with the Rams missing receivers Cooper Kupp and Puka Nacua, as well as tight end Tyler Higbee, who’s still recovering from a severe knee injury from January. The 49ers were without running back Christian McCaffrey, receiver Deebo Samuel and tight end George Kittle.

All the more reason that sturdy starters such as Williams needed to step up. And the Rams didn’t scrap the running game, even when they trailed by as many as 14 points and the game appeared to be slipping away.

The run threat created opportunities in the passing game and helped the Rams move the ball effectively in the red zone, something they couldn’t reliably do in road losses at Detroit and the Cardinals.

Williams didn’t put up stratospheric numbers — 89 yards in 24 carries — but he was a hammer near the goal line, scoring on runs of three and four yards.

Rams running back Kyren Williams picks up yards against the 49ers. He scored three touchdowns, two on the ground.

(Wally Skalij / Los Angeles Times)

Just before the winning 37-yard field goal by Joshua Karty, Williams had a six-yard run that helped consume 31 seconds from the clock and turned a gut-check kick into a layup.

“We got some really tough, hard-earned yards in some crunch-time situations,” said McVay, whose offensive line included guard Logan Bruss, making his first career start. “Some short yardage, some third down and two or less. I thought our guys did a good job of removing the line of scrimmage.”

This didn’t show up in the statistics, but he was instrumental when it came to chip blocking pass rusher Nick Bosa coming off the edge, helping keep Stafford upright.

Williams also was concerned about keeping something else in check: his emotions.

“I don’t really try to get too excited,” he said. “I try to stay even-keeled because I know when you get excited and you start expecting things those things don’t come.”

No one saw this ending coming.

And Williams didn’t pay much attention to the 49ers fans going, either.

They were in the vast majority, painting every SoFi Stadium section red.

Did Williams hear the crowd?

“Naw, I didn’t hear it,” he said, finishing the interview. “Play ball, baby.”

Maybe he did stick the landing after all.