McIlroy, playing in the afternoon group on day one, was bogey free in his round of 65 during an afternoon in which a range of conditions were thrown at him. Early in the round it was wind and late in the day it was rain but he appeared almost oblivious to it with a brilliant first day.
"I don't think conditions were that easy," said McIlroy. "You know, there was a little bit of a breeze out there, and the greens were getting pretty firm. A few of the greens around the holes were getting pretty chewed up, as well. It was tricky out there, but I just managed to keep the ball in the fairway and find a lot of greens, and that was basically how I shot that score.
Inevitably the topic of Sunday at Augusta National where he lost a significant lead on the final day was raised and the youngster handled it in his stride. "I took the experience from Augusta, and I learned a lot from it. But I feel like these good starts in the majors are very much down to my preparation and how I prepare for them. But yeah, I mean, you can't you're going into the U.S. Open. You can't be thinking about what's happened before, you've got to just be thinking about this week and how best you can prepare and how you can get yourself around the golf course."
So what was it that he took out of that experience? "I just took mostly from the Sunday just being so tentative and trying to keep ahead of the field instead of playing a free flowing game like I usually do. That's one of the big differences.
Three shots back of McIlroy are Y.E. Yang and Masters Champion Charl Schwartzel, the fact that two of the leading three scores on day one came from the afternoon group being quite a surprise.
Schwartzel was delighted to have driven it so well all day. It was tough. "We had a little bit more wind than what we've had in the practice rounds, which does play quite a bit of effect," said Schwartzel.. "But I was saying to my caddie that I drove it well, so I felt like I was giving myself good chances. I think that's a big key. I was in the fairway and I actually felt like I could make a good score.
The expected thunderstorms never eventuated but rain hampered play a little late in the day. It also reduced the ever increasing firmness of the golf course.
Some of the bigger names were a disappointment. Luke Donald, Phil Mickelson and Martin Kaymer recorded a rounds of 74 and Lee Westwood 75.
The leading Australian after day one and a great result for him was Scott Hend who after missing the cut in Italy last week in what was a rushed trip returned to produce a fine round of 69 which included a back nine of 32.
John Senden also did well with a round of 70 to be at 1 under while Jason Day and Aaron Baddeley are at even par.