LOS ANGELES — With many of their starters resting, the Rams struggled to find their rhythm on offense falling to the 49ers 34-13 in Los Angeles' regular-season finale.

Although it wasn't an ideal outcome for the Rams — with a New Orleans' loss — L.A. still held on to its No. 3 seed in the NFC playoffs and will host the Falcons next Saturday.

"I think anytime you go into a football game, you're certainly going to try to win the game," head coach Sean McVay said. "[But] I do think when you look at the way we approached it, we feel good about being able to allow some of our players to get some rest. And that was a great job by the 49ers today."

San Francisco got on the board first with a 33-yard field goal early in the first quarter. Quarterback Jimmy Garoppolo and the Niners made quick work down the field — going 60 yards in just four plays. But the Rams were able to apply strong pressure in the red zone, holding the Niners to three.

But the visitors would score a first-quarter touchdown to extend their lead. Starting on the San Francisco 18, the Niners took eight plays and 82 yards to make it to the endzone.

During the drive, Garoppolo held his composure under pressure — hitting tight end George Kittle and wide receiver Marquise Goodwin for 17- and 20-yard gains. A few plays later, Garoppolo hit Goodwin in the flat for an eight-yard touchdown.

The Rams' offense — led by quarterback Sean Mannion — struggled to get in sync early on, but was able to put points on the board with a little help from the defense.

On 1st-and-10 from the SF 41, cornerback Kevin Peterson — who was starting in place of Trumaine Johnson — jumped in front of a pass intended for Goodwin to record the Rams' 17th interception this season.

Peterson said he knew he "was going to get a lot of opportunity in this game," and was hoping to capitalize on his first start of the season.

"I just did a lot of film study," Peterson admitted. "They came out in a formation I recognized and we had a call that matched well with that formation. I just went out and got it. Put my hands up and prayed that I caught it."

Peterson's 38-yard return put Los Angeles well within field goal territory and kicker Sam Ficken finished the drive, nailing a 23-yard attempt. That score cut Los Angeles' deficit to seven.

Johnny Hekker boomed a 48-yard punt midway through the second quarter to pin the Niners back at their own endzone. But the visiting team was able to run their way out of the hole thanks to running back Matt Breida.

San Francisco kicker Robbie Gould connected on a 48-yard field goal to cap the drive and put the Niners up by 10.

With two minutes left in the half, the 49ers executed an impressive drive to give San Francisco a 20-3 lead. A personal foul by safety Blake Countess put San Francisco on Los Angeles' eight. And running back Carlos Hyde capitalized on the favorable field position — punching in an touchdown with a run up the middle.

And with just 26 seconds remaining, Mannion was sacked for the second time, fumbling the ball in the process. Though San Francisco recovered the loose ball, Peterson intercepted Garoppolo's pass on the ensuing play giving L.A. possession for the final drive of the first half.

Peterson's two interceptions on Sunday are the most in a single game since Trumaine Johnson picked off two passes against Oakland in 2014. 

"You know our coaches always tell us to stay ready and prepare like you're going to be a starter because you never know what's going to happen," he said. "I tried to put a bunch of good stuff on tape."

An impressive 50-yard catch by wide receiver Michael Thomas, set up a 21-yard field goal for Ficken. The score cut San Francisco's lead to 20-6 headed into halftime.

The Penn State product was perfect on the night nailing two field goals and one extra point attempt. McVay said he was proud of the way Ficken was able to bounce back after missing two early attempts in Week 16.

"I think he did a nice job today, made the most of his opportunities, and had some good kickoffs as well," McVay said. "I would have liked to have given him a few more shots, but I think for him to come in here definitely an [improvement] from the previous week. Pleased with Sam today."

But it was much of the same for the Rams in the third quarter, as the offense struggled to find its rhythm and was held to consecutive three-and-outs. Things didn't look much better for the L.A. defense, as San Francisco's seven play, 60-yard drive gave the Niners a three-score lead.

Breida kick-started the drive with an 11-yard run to the left and then Garoppolo found tight end Garrett Celek on a 28-yard pass to set up a rushing touchdown — Hyde's second of the day.

With 3:33 remaining in the third, the Rams' bad luck continued as tight end Gerald Everett committed the club's second turnover of the day with a fumble. San Francisco's K'Waun Williams recovered the ball at the Niners' 47-yard line.

Garoppolo and company found the end zone once again just seven plays later. 

On third-and-eight from the Los Angeles 12-yard line, the quarterback dropped back and delivered a dime to wide receiver Aldrick Robinson. The score put the Niners ahead 34-6.

It took Los Angeles 15 plays and more than eight minutes to drive downfield, but the Rams finally struck pay dirt late in the fourth quarter.

"Disappointed we didn't come away with a win," Mannion said. "But that being said, at least we got it going and had a long efficient drive late in the second half."

On 1st-and-goal from the San Francisco eight-yard line, Mannion handed the ball off to running back Lance Dunbar. The North Texas product muscled his way into the endzone for his first touchdown of the season — cutting the Rams' deficit to 21 points.

The Niners were able to wind down the clock in victory formation, coming away with a 34-13 win.

With the loss, the Rams will finish the regular season 11-5. It's an impressive turnaround for the club, which went 4-12 just one year ago. Next Saturday, the Rams will host a Wild Card game against Atlanta at the Coliseum marking the franchise's first playoff appearance since 2004.