At least on Thursday.
Showing no linger effects from a Sunday collapse at the Masters Tournament, the 22-year-old McIlroy made the toughest test in golf look like child's play at Congressional with 6-under-par 65.
He was the only player in the 156-man field without a single bogey. And just like that, McIlroy wound up atop the leaderboard after the opening round for the third time in the past four majors.
There were questions about how McIlroy would respond after the calamity of his most recent round in a major, when he squandered a four-shot lead at Augusta National with 80 in the final round. He has been saying ever since that he got over that meltdown a week after the Masters. By the way he bounced back at the U.S. Open, maybe it's time for everyone to believe him.
He took a route unlike any other player on an overcast day with a few light showers just as he finished up his round.
McIlroy was three shots clear of former PGA champion Y.E. Yang and Charl Schwartzel, the South African who captured the Masters two months ago at McIlroy's expense.
"It's a long way to go, but it's nice to get yourself in contention," Schwartzel said. "If you start falling too far behind on a tough golf course, things can get a little bit too far in front of you. You need to stay in there with a chance."
British Open champion Louis Oosthuizen had 69, joining a small group that included Sergio Garcia and Ryan Palmer, the lone American among the nine players who broke 70.
Defending champion Graeme McDowell had 70.
Phil Mickelson played alongside McIlroy.
"The game's easy when you hit it straight and make every putt," Mickelson said, referring to McIlroy. "It's a wonderful game. No course is too tough when you hit like that. He played terrific. It was fun to watch -- although I didn't see much of it."
McIlroy became the 10th player to start the U.S. Open at 65 or better, yet only two of them went on to win -- Jack Nicklaus in 1980 at Baltusrol and Tiger Woods in 2000 at Pebble Beach. And of the previous eight players to hold a three-shot lead after the opening round -- Jerry Pate in 1976 was the last one -- only Ben Hogan in 1953 at Oakmont wound up with the trophy.
Mickelson wound up with 74.
Mickelson wasn't alone in his disappointment.
The top three players in the world -- Luke Donald, Lee Westwood and Martin Kaymer -- combined to go 10-over par. Donald struggled with his accuracy and couldn't cope with the thick rough and shot 74 despite his birdie-birdie start. Kaymer also had 74, while Westwood staggered to 75, his worst opening round at the U.S. Open in 10 years.