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The Northern Ireland world number three, playing alongside Englishman Chris Wood, aced the par three 16th hole with a seven iron from 170 yards.
"It was a nice practice round and a bit of a highlight, and it ended the match as well," said Mcllroy.
"I played well. I feel like my game is in good shape."
McIlroy, who is looking to become only the sixth player to complete the career Grand Slam with victory this week, had singled out the 16th as a key hole but did not expect to begin his eighth Masters campaign with an ace.
"The 16th is not a pushover especially when the pin is over on the right, but then you have a decent chance when the pin is on the left," he said.
"The course is 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. I'm sure they are trying to get it faster and firmer as the week goes on."
The golfer arrived at Augusta on Sunday night, admitting he spent the first three days of last week as a 'couch potato' before hitting the Bears Club on Thursday in the company of his long-time coach Michael Bannon and fitness coach, Steve McGregor.
"I had three days off early last week and then Michael and Steve got into town on Thursday and started working then," he said.
"It was only two weeks in a row, but Austin felt like a long week so three days off was good, and besides the weather wasn't very good so I sat on the couch and caught up on some TV.
"I also played the one ball off the tees today and that gets me into a nice mindset of this is how I'm going to play, so I'm going to try to do the same tomorrow."
Rory McIlroy said he'd "never heard a roar that large" after his hole in one on the first day of official practice for the Masters at Augusta.