LOS ANGELES -- Behind a large contingent of fans chanting, "Let's go, Niners!" at the L.A. Memorial Coliseum on Sunday, the San Francisco 49ers defeated the Los Angeles Rams 20-7, delivering the Rams their third consecutive loss of the season.

It's the first time since Sean McVay was hired as coach in 2017 that the Rams have lost three straight games. The skid comes a season after McVay led the Rams to an NFC championship and a Super Bowl appearance.

"Was it a humbling day for us? Absolutely," McVay said after the game. "But it's something that we're going to learn from. We're not going to let it demoralize us."

Quarterback Jared Goff passed for a career-low 78 yards, completing 13 of 24 passes. He was sacked four times. Goff's previous low was set in 2016, his rookie season, when he passed for 90 yards in a 22-21 loss to the 49ers.

"It's a gut check," Goff said about the losing streak. "Are you who you say you are? I know who this team is. ... We're going to get right back on track."

The Rams played Sunday without running back Todd Gurley, cornerback Aqib Talib and outside linebacker Clay Matthews, who were all inactive because of injuries.

Running back Malcolm Brown started in place of Gurley and rushed for 40 yards on 11 carries. Rookie Darrell Henderson rushed for 39 yards on six carries. He also lost a fumble on the Rams opening drive of the second half.

The Rams took an early 7-0 lead on a 7-play drive, as Brown rushed for 40 yards on five carries and receiver Robert Woods rushed for 16 yards on 2 carries, including an 8-yard touchdown run.

But the 49ers scored 20 unanswered points behind a 2-yard touchdown run by Tevin Coleman and a 1-yard run by quarterback Jimmy Garoppolo.

The Rams had the chance to cut into the 49ers' 20-7 lead with 8:49 to play when defensive tackle Aaron Donald strip-sacked Garoppolo, and linebacker Cory Littleton recovered, then tossed a lateral to cornerback Nickell Robey-Coleman, who stepped out of bounds at the 49ers' 36-yard line. But the Rams were unable to convert the takeaway into points, as they were stopped on fourth down.

"It goes back to the consistency I always talk about," Goff said. "It's something we are struggling with offensively."

"This is tough," said Woods, who did not record a single catch. "We're competing, battling, going out there and just not executing."

The Rams went 0-for-9 on third down. It was their first game without a third-down conversion since they went 0-for-11 against the Philadelphia Eagles on Sept. 7, 2008.

And their offensive inefficiencies didn't stop there. The Rams also went 0-for-3 on fourth down. The last time they went for it on fourth down at least three times with no conversions was against the Seahawks on Dec. 15, 2016, when they went 0-for-4.

"We came out and started fast, but it comes down to consistency," Woods said. "We look like a good offense sometimes, look like a bad offense. Just not being consistent."

Rams left guard Joe Noteboom left the game in the first quarter because of a knee injury, and safety John Johnson was sidelined in the second half because of a shoulder injury.

The Rams were upset in Week 4 by the Tampa Bay Buccaneers 55-40, then fell to the Seattle Seahawks 30-29 after Greg Zuerlein's 44-yard field goal attempt missed wide right with 15 seconds to play in Week 5.

The Rams (3-3) are in third place in the NFC West behind the 49ers (5-0) and Seahawks (5-1), putting their run at a third consecutive division title in jeopardy.

"I trust that this is a mentally tough team," McVay said. "We have mentally tough people in our building. This is a real opportunity to be what we say we are, and we are just going to go to work. We are going to stay together. We're not going to let the outside influences create a divide with us."

The Rams now will play a host of teams with losing records as they travel away from the Coliseum for the next month. They are scheduled to take on the Atlanta Falcons (1-5) next Sunday at Mercedes-Benz Stadium, then will travel to London to play the Cincinnati Bengals (0-6) in Week 8 before a Week 9 bye. In Week 10, the Rams return to the East Coast to play the Pittsburgh Steelers (1-4).