Updated 7:40 p.m. PT

LOS ANGELES — It was a back-and-forth game from start to finish, but in the end the Rams could not come up with enough plays to defeat the Eagles, falling 43-35.

Los Angeles held a slim one-point, 35-34 lead midway through the fourth quarter. But a pair of former Rams — defensive end Chris Long and safety Rodney McLeod — combined on a strip-sack and fumble return to put the Eagles in position to take the lead with a field goal. Though the Rams had another chance to score, the offense went three-and-out and had to punt just before the two-minute warning.

That's when the Eagles were able to convert their eighth third down of the game, leaving the Rams with only one second on the clock at their own 24 after a punt.

Philadelphia would foil Los Angeles' final play, returning it to the end zone for a cosmetic touchdown.

"Tough football game today," Rams head coach Sean McVay said postgame. "We played against an excellent opponent. They made more plays than we did in the end."

Sunday's contest was also filled with a litany of injuries to both sides. Quarterback Carson Wentz left the contest after an Eagles touchdown drive in the fourth quarter with a knee injury the team fears is a torn ACL, according to ESPN’s Adam Schefter.

And McVay confirmed the Rams lost cornerback Kayvon Webster to a ruptured Achilles tendon, which will keep him out for the rest of the season.

"Very unfortunate. Kayvon is a great competitor," McVay said on Webster, who had an interception in the contest. "We love Kayvon and what he's meant to this football team, and guys are going to need to step up in his absence."

"Kayvon is my guy. Me and Kayvon go back all the way to high school, so it means a lot to me that he is hurt right now," cornerback Nickell Robey-Coleman said. "I pray nothing but the best for him, his recovery and his family."

Cornerback Trumaine Johnson has also entered concussion protocol, which could leave the Rams a bit thin at cornerback.

"It's tough, it's really tough," safety Lamarcus Joyner said. "But it's next man up — that's just what kind of league it is."

While Sunday was a up-and-down affair from a football standpoint, penalties were a key factor in the Eagles ending the game. The visitors finished with 29 first downs, six of which came via penalty. A pair of early defensive pass interference penalties put the Eagles in position to score touchdowns. And then an unsportsmanlike conduct penalty in the third quarter turned what was an incomplete third-down pass into an eventual touchdown as well.

"Anytime [you're] in a hard-fought game, a tough game — you get penalties like that, it's going to hurt you," defensive tackle Aaron Donald said.

"I will say this, it provides an opportunity for us to learn from. We can't beat ourselves," McVay said. "We've got the right guys in that locker room from a football-character standpoint to take accountability for the things that we can control — and this is coaches and players alike. But, what we're not going to do is we're not going to beat ourselves. Unfortunately, there were some instances today where we gave them some free first downs because of things that we can control. And I trust our guys will respond the right way as we move forward."

In the end, L.A. ran just 45 plays to Philadelphia's 85 as the Eagles outgained the Rams, 455 yards to 307 yards.

"We didn't get enough opportunities," McVay said. "We've got to do a better job early on of sustaining drives by converting on third downs. We had a couple third-and-manageables where they did a great job creating somme pressure [and] the ball had to come out."

The Rams did get off to a hot start on Sunday, ending their opponent's opening drive with an interception for the second consecutive week. On 3rd-and-5, cornerback Nickell Robey-Coleman tipped a ball away from wideout Nelson Agholor, and Webster dove and secured the ball before it hit the ground.

Running back Todd Gurley broke off a 30-yard run before scoring on a two-yard run to give the Rams a quick 7-0 lead.

But the Eagles came back to score 21 straight points, with Wentz throwing three touchdowns to tight ends. With Zach Ertz inactive due to a concussion, backups Brent Celek and Trey Burton stepped up. Wentz first hit Celek with a five-yard touchdown pass, then went to Burton for a 20-yard scoring strike, before finding Burton again with an 11-yard TD with 11:10 left in the first half.

Down 21-7 and needing a spark, the Rams found one in wideout Cooper Kupp. On 3rd-and-10 from the L.A. 25, Goff hit the rookie with a pass just beyond the sticks on the left side and Kupp made a few defenders miss down the left sideline for a 64-yard gain.

That play put Los Angeles inside the red zone, and Kupp would finish the possession with a six-yard touchdown reception. He ended the day with 118 yards on five catches, setting a new Rams rookie record with 56 receptions in 2017.

Eagles kicker Jake Elliott connected on a 22-yard field goal with nine seconds left in the second quarter, giving the Eagles a 10-point lead at halftime.

The Rams began the second half strong, marching down the field for a 71-yard touchdown drive. Gurley started the possession with a 17-yard run, and also took a screen pass 20 yards. But it was wide receiver Sammy Watkins who finished it, making a one-yard reception for his team-leading seventh touchdown of the year.

Then Los Angeles got another big play from its special teams unit, as wide receiver Mike Thomas blocked Donnie Jones' punt following a Philadelphia three-and-out. Safety Blake Countess picked up the loose ball, returning it 16 yards for a touchdown.

"Mike Thomas ends up coming free and Blake Countess is able to deliver, finishing that play," McVay said of the Rams' third blocked punt of the season — the second that's been returned for a touchdown. "That's kind of the theme for the year when you look at the way special teams has played."

The Eagles' ensuing drive lasted 15 plays and went 75 yards, with a significant unsportsmanlike conduct penalty on Trumaine Johnson extending the possession following a Wentz incompletion on third down.

"[T]hey said that these guys had been talking, going back and forth, and there had been some warnings going on, and that was the decision that the side judge made," McVay said of the explanation he received on Johnson's penalty. "Those are things that we have to respect and we have to handle the right way, and I trust that we will as we move forward."

Wide receiver Alshon Jeffery caught a two-yard touchdown on 4th-and-goal from the L.A. two, making an outstanding catch on a low throw from Wentz.

But that was the last throw Wentz would make, as he exited the game following that possession. The quarterback had run in what appeared to be a touchdown that was nullified by offensive holding and appeared to be hit in the leg on that play.

Nevertheless, the Rams got back on top with more solid running from Gurley. The running back commenced the possession with a 21-yard run and ended it with a one-yard touchdown to put L.A. up 35-31.

With backup Nick Foles in at quarterback, the Eagles were able to cut the lead to one with a 41-yard field goal. And just as the Rams looked like they were going to put something together in response, Long strip-sacked Goff to put the Eagles in position to take a two-point lead. Elliot converted on his 33-yard try and Philadelphia was up 37-35.

Los Angeles had a chance to come right back and score, but got behind the chains after only one play. Gurley was stuffed for a three-yard loss on first down. And while Goff scrambled on second down to get the Rams back to 3rd-and-10, his third-down pass to Watkins was incomplete.

With three timeouts and the two-minute warning as ways to stop the clock, the Rams punted. And it looked like the Rams would have a chance, the defense put the Eagles at 3rd-and-8. But Agholor made a nine-yard catch to extend the visitors' drive and essentially end the game.

The Rams got the ball back with a second left after Pharoh Cooper's fair catch on a punt. But Los Angeles' last-ditch play was fumbled and returned to the end zone for a touchdown as time expired. Philadelphia took a knee on the extra-point attempt to end the game.

Though they fell to 9-4, the Rams will maintain their one-game lead in the NFC West because the Seahawks fell to the Jaguars on Sunday. Los Angeles and Seattle will meet next week at CenturyLink field for an important divisional matchup.

"This week provides a great chance for us to respond quickly, go play a great divisional opponent in the Seattle Seahawks, and try to see if we can find a way to gather ourselves together to learn from the mistakes and move forward accordingly," McVay said. "What this team has done week-in and week-out is we've responded the right way. I trust our guys will do that."