ST. LOUIS -- Entering Sunday's game against the New York Giants, the St. Louis Rams defense was playing about as well as any in the league over the past eight weeks.

Included in that performance was a streak of 12 quarters without allowing a touchdown, two shutouts -- against the Oakland Raiders and Washington Redskins -- and a gem in which they held the Denver Broncos and quarterback Peyton Manning to the fewest points -- seven -- of Manning's tenure in Denver.

Those numbers were likely unsustainable for any defense but nobody expected what came in Sunday's 37-27 loss to the New York Giants. Fittingly, it was the younger Manning brother, Eli Manning, who was at the controls of an offense that made a previously extraordinary defense straining to reach ordinary.

By the time Manning and Co. were done, they had laid waste to the Rams to the tune of 514 yards of total offense, including Manning's 25-of-32 for 391 yards and three touchdowns.

"To give up 500 yards is embarrassing," linebacker James Laurinaitis said. "They made all the plays today. We didn’t get a takeaway. We didn’t do enough just period in every facet of the defense. It was self-inflicted stuff. That’s the thing that really gets you upset because you think you’re past it.

"It’s cliché but it’s just back to work, fix our mistakes and try not to repeat them. This business is all about not being repeat offenders of the same mistake, if they are, they take it and you get replaced."

Sunday's performance probably left many Rams fans searching for possible replacements. New York's 37 points were the most allowed by the Rams this season and second most allowed by a Rams team since Jeff Fisher took over in 2012. The 514 yards of offense allowed were the most by a Rams team under Fisher.

While those monster offensive days have been rare against the Rams under Fisher, there were plenty of plays making up those yards that have become all too familiar. None more so than the 80-yard touchdown pass from Manning to rookie receiver Odell Beckham Jr. in the third quarter.

After a Rams touchdown made it 27-20, the Giants faced third-and-10 from their 20 with 55 seconds left in the third. On the previous play, starting cornerback E.J. Gaines had suffered a concussion that removed him from the game and brought rookie corner Lamarcus Joyner in his place.

Joyner lined up in the slot over Beckham with Trumaine Johnson on the outside receiver. At the snap, Beckham broke to the outside with outside receiver Rueben Randle coming underneath. Both Johnson and Joyner stayed with Randle, leaving Beckham with a free run into the Rams secondary where only safety Mark Barron awaited.

You can guess how that movie ended.

"It was a mental error by both guys, a miscommunication, something that we’ll go back and fix," Joyner said. "Technique and uncommon errors by guys. We gave up a touchdown. We were in two-man and we were supposed to in and out that, the defense has been playing well and it was my first time back out there so when you’ve got a new guy you need continuity and things kind of went south."

It was a play eerily reminiscent of the 68-yard touchdown catch by Dallas receiver Dez Bryant earlier this season when the Rams busted the coverage and failed to cover the most dangerous player on the field. If Randle makes a catch, it might go for a solid gain and a first down but if Beckham gets it, well, you know the rest.

Manning was 6 for 8 on passes traveling at least 15 yards in the air, twice as many as the Rams had allowed in their past four games combined. He also was able to pinpoint Rams' blitzes to great effect, going 13-of-15 when the Rams sent five or more rushers.

But instead of just one or two big breakdowns, there were many for this Rams defense. Giants running back Andre Williams had 110 yards on 26 carries, including 65 yards after contact as the Rams failed to tackle sufficiently. Even the Rams' revved up pass rush downshifted with only one sack, none from the defensive line, as Manning was 6 for 7 for 181 yards and a touchdown when he was pressured.

"I thought we were beyond that," Laurinaitis said. "But when you have miscommunication or whatever happened on plays or you drop coverage and you don’t play certain techniques right or you’re bad on third down, stuff that we hadn’t done, it's uncharacteristic to the way we had been playing."