Northern Irishman McIlroy -- one of the favorites to win the tournament and complete a golfing grand slam by winning every major -- shot a 170-yard hole-in-one at Augusta National's 16th on Monday.
His magic moment came in a practice match against English player Chris Wood when, using a seven iron, he hit the perfect shot to electrify the crowd.
"I have never heard a roar that large in a practice round," McIlroy told reporters
. "It was great.
"It had been a nice practice round, and that was a bit of a highlight. The 16th is not a pushover.
"I played well. I feel like my game is in good shape."
Wood, whose defeat in the practice match was sealed by McIlroy's moment of inspiration, said: "When he closes out with a hole in one, you can't really do a lot about that.
"I've never quite heard a noise like it. It was pretty mad. It was great fun. It was a cool moment.
"He's a quality, quality player. I've played with just about everybody now and Rory is up there with everyone. Very, very impressive. He's going to be a favorite every year he comes back here, and this year is no different."
McIlroy, who came fourth in the tournament last year, added that he felt this year's course was "not very different at all from what we saw last year."
"I feel like the way the course is now is probably the way the course played last year because it was soft and a little slow," he added.
"I'm sure they are trying to get it faster and firmer as the week goes on."
World No. 3 McIlroy has decided to skip the Masters' Par 3 contest
on Wednesday. The only other year he hasn't played the nine-hole exhibition since his Augusta debut was in 2011, when he led the Masters by four shots in the final round but collapsed with a nightmare 80 and finished 15th.
The Par 3 competition was first held in 1960, but none of its winners has managed to follow it up with Masters success that same year.