INGLEWOOD – Jauan Jennings’ three touchdown catches — and 11 receptions overall for 175 yards — should have been enough for the 49ers to bury a wounded Rams team Sunday.

Instead, the 49ers blew it.

The shorthanded Rams pulled out their first win of the season by rallying from a 24-14, fourth-quarter deficit to claim a 27-24 home-opening victory at SoFi Stadium, where the majority of fans wore red 49ers jerseys — and unhappy faces as they exited.

“I know everyone was pissed without them having to tell me. And we should be,” coach Kyle Shanahan said of the locker room scene. “When you have a game like that, where you feel you have every chance to win and don’t get it done, those are usually the more disappointing ones. All three phases had their (say) in that.”

As was the case in the 2021 season’s regular-season finale here, the 49ers blew a 10-point fourth-quarter lead.

Joshua Karty’s 37-yard field goal with two seconds remaining gave the Rams their first lead — and the only one they needed to hand the 49ers (1-2) a second straight road loss.

“We need to feel the loss. We can’t move on and think it’s fine,” defensive end Nick Bosa said.

The 49ers attempted a seven-lateral desperation play in the final seconds and reached Rams territory before Jake Brendel’s toss to Brandon Aiyuk bounded out of bounds to end one of the 49ers’ most frustrating losses in years. It was also their first regular-season defeat at SoFi Stadium in five years.

The 49ers, after back-to-back road games, return to Levi’s Stadium to host the New England Patriots and then the Arizona Cardinals over the next two Sundays. The Rams avoided their first 0-3 start since 2011, when they were stationed in St. Louis and finished 2-14 that year.

“It’s definitely a rough start but there’s a ton of football to be played,” Bosa said. “We’ve been through rough stretches before. We have to stay together and we have the guys to do it.”

Do they, though? The 49ers played Sunday without three offensive stars — running back Christian McCaffrey (Achilles; injured reserve), wide receiver Deebo Samuel (calf), and tight end George Kittle (hamstring).

Of Jennings’ 11 receptions for 175 yards, three came on the offense’s final series, when they needed one more catch from him or anyone else. Afterward, he got dressed at his locker, declined to speak to reporters and exited the locker room, having done enough talking on the field.

The 49ers needed their defense to protect a 24-17 lead with 2:43 remaining. They couldn’t. Rams running back Kyren Williams matched Jennings with a third touchdown in this NFC West battle, tying the score at 24 with 1:51 to go in regulation. That game-tying drive by the Rams opened with Matthew Stafford completing a 50-yard strike to Tutu Atwell at the 5-yard line against Charvarius Ward’s coverage.

The 49ers’ ensuing drive didn’t even take a minute off the clock, hindered most by a Ronnie Bell drop of a long second-and-10 pass deep in Rams territory.

That offensive failure, which followed 49ers defensive failures, set the stage for yet another special teams gaffe. On a day the momentum swung on a Rams fake punt, Jake Moody missed a 55-yard field goal with 2:43 remaining and the special teams’ final blow was allowing a 38-yard punt return to reach midfield, setting up the Rams’ deciding field goal.

The 49ers had settled for a 26-yard field goal from Moody for a 24-14 lead, seemingly healthy enough to protect over the game’s final 12 minutes. That 13-play, 62-yard scoring drive opened, of course, with Jennings’ catches of 32 and 14 yards, then Brock Purdy’s runs kept the sticks moving until Moody was summoned.

The Rams responded with their own field goal, a 33-yarder that followed Sam Okuayinonu’s third-down sack.

The 49ers figured to have scored their win-clinching play when Purdy connected on a 31-yard touchdown pass to Jennings, who kept running through the end zone into the SoFi Stadium tunnel with his right index finger pointing in the air. That made it 21-7 and was the dagger the 49ers needed, the type of third-down conversion that proved this offense could survive without McCaffrey, Samuel and Kittle.

However, Jennings’ third score came only midway through the third quarter. That allowed ample time for a Rams comeback. Purdy threw touchdown passes to Jennings on the 49ers’ opening two drives, and it looked like a rout was on, until the Rams resorted to a fake punt to keep alive a touchdown drive and pull within 14-7.

Jennings’ only previous game with two touchdown receptions was here in the 2021 regular-season finale, a 27-24 win. He entered this visit anticipating plenty of targets, and he delivered some heroics that triggered memories of his two-touchdown show in February’s Super Bowl loss.

Purdy completed 22-of-30 passes for 292 yards, and he also ran 10 times for 41 yards to give the 49ers a complementary rushing effort next to starter Jordan Mason, who had 19 carries for 77 yards after reaching 100 yards in each of his two preceding starts in place of McCaffrey.

While so much pregame focus was on whether Brandon Aiyuk would live up to his extension paying $30 million annually, it was Jennings who produced in the red zone and further validated the two-year, $15 million contract he signed in May as an apparent bargain. Jennings’ most acrobatic catch came in the third quarter: an over-the-back, 32-yard reception. Purdy went back to Jennings two snaps later for a 14-yard grab amid three defenders.

After Jennings’ third touchdown, the Rams answered with their own touchdown drive, capped by Kyren Williams’ 3-yard scoring run once Renardo Green’s holding penalty set up first-and-goal. Williams scored the Rams’ previous touchdown on a 15-yard catch-and-run-and-flip over the goal line 1:11 before halftime to pull the Rams within 14-7.