"To be able to come in on such short notice, with such short practice time and to be able to play the way that he did, it was a big boost to our team for sure," Rams coach Sean McVay said.
Ramsey was inserted on the third play of the game and finished with four tackles and a forced fumble. He was tasked with defending Falcons All-Pro receiver Julio Jones, who finished with six catches on nine targets for 93 yards, though Ramsey was not in the game for an early 5-yard reception or a late 19-yard catch.
"I feel like I played OK," said Ramsey, who practiced twice with the Rams before Sunday's game. "I got to get in my groove a little bit more, it's just maybe one, maybe two plays that I wanted to have back or play a little bit different, but I thought it was good."
Ramsey allowed Jones to catch passes of 13, 17 and 39 yards.
The Rams held the Falcons to 38 rushing yards and 224 total yards. The Falcons' 10 points scored tied their season low. Outside linebacker Dante Fowler Jr. sacked Falcons quarterback Matt Ryan three times, and defensive tackle Aaron Donald and linebacker Cory Littleton each added sacks.
The defense was able to dominate despite a limited playbook.
"Honestly, the defense was a little dumbed down for me, just because I only had a couple days to prepare," Ramsey said. "I really appreciate the guys kind of going with the game plan because it probably wasn't -- I'm not going to say it wasn't the best for them, because they went out there and they strapped, too -- but just kind of appreciate everybody's help these couple days I've been here, these few days I've been here."
Said veteran safety Eric Weddle, the defensive signal caller: "It's exciting for me, because we probably got 30 percent of our defense in, so getting into a lot of the other stuff that we do, so [Ramsey] can actually rep it, practice it and study it, it's only going to make him more dangerous, and us as a defense, to keep teams on their heels."
Fowler spent 2 1/2 seasons with Ramsey in Jacksonville before he was traded last October to the Rams. Fowler, who is playing this season on a one-year, $12-million deal, called it "surreal" to play alongside Ramsey again.
"It was awesome," said Fowler, who had seven tackles, a pass deflection and a forced fumble to go along with his three sacks. "I was like, 'Wow, he's really out here on the field with me.' ... It's going to be a special ride."
The Rams sent first-round picks in 2020 and 2021 and a fourth-round pick in 2021, to the Jaguars in exchange for Ramsey, who requested a trade following a Week 2 sideline dispute with Jaguars coach Doug Marrone.
Ramsey did not play the last three weeks in Jacksonville because of a back injury, but passed his physical with the Rams on Wednesday and practiced the following two days.
"I don't think you can say enough about his ability to digest the game plan," McVay said. "He's kept himself in good shape. I know he had the back thing, but [he] ended up feeling pretty good."
Ramsey said it was "dope" lining up on a defense that included Donald, the two-time defending NFL Defensive Player or the Year, and Fowler, and he expressed confidence his play will improve after he acquaints himself better with his new teammates.
"I want to get in a groove, knowing my safeties a little bit better, knowing the guys I'm out there with a little bit better," Ramsey said. "This game I really trusted in them a lot, the way I play certain techniques, but I want to get in a groove a little bit more with how I do things with this secondary."