McIlroy, who won his first Green Jacket last year, opened his title defence with a five-under-par 67 for a share of the lead and said the familiar anxiety on the opening tee was a sign that Augusta National still mattered as much as ever.
"If I felt absolutely nothing on that first tee, that's not a good sign," McIlroy told reporters.
"So it was nice to feel my hand shaking a little bit when the tee went into the ground and struggle to put the ball on top of the tee.
"So I knew I was feeling it. That's a good thing."
The Northern Irishman said the nerves were no different from previous visits, even after finally breaking through for a Masters title and completing the career Grand Slam in 2025.
"I'm thankful that I felt the same as I always have," he said. "I think it would be worrisome if I didn't feel that way because it definitely still means something to me."
Settling in
McIlroy's scorecard suggested a smooth start, with six birdies against a lone bogey, but the opening stretch was anything but tidy.
He spent much of the first seven holes playing from the trees before finding his rhythm from the eighth onward and playing his final 11 holes at five under for his lowest opening round at the Masters since 2011.
Rather than panicking, McIlroy said he trusted that his swing would return and leaned on experience to avoid bigger mistakes.
"I didn't compound errors," he said. "I got up-and-down when I needed to."
That patience, he suggested, may be one of the benefits of already having won at Augusta. McIlroy said claiming one Masters title made it easier to chase another, even if there were still moments of tension.
"I think winning a Masters makes it easier to win your second one," he said, before delivering the line of the day about the comforts of being champion.
"I think it's easier for me to make those swings and not worry about where it goes when I know that I can go to the Champions Locker Room and put my Green Jacket on and have a Coke Zero at the end of the day."
McIlroy said his focus for Friday would be to find more fairways, especially with the greens expected to get firmer and faster as the week goes on.
But for a player who once carried the burden of unfinished business at Augusta, Thursday offered a different kind of reassurance - the nerves were still there, and so was the belief.