“I played my first one in ’09, and I think I really changed my mindset around them in 2019, that one in Pebble, and then since then I’ve also started to enjoy this style of golf a lot more.
“It’s a lot different than the golf that we play week in, week out.”
McIlroy opened with three stress-free pars in the marginally more difficult afternoon conditions before making two birdies in a row, ripping a 211-yard approach to seven feet at the fourth before chipping in for another birdie at the par-five fifth.
When he did miss a green, he scrambled for par, getting up and down at the sixth and eighth to turn in 33.
The Co Down man (35), who had only fours and threes on his card, two-putted for birdie at the par-five 10th before following a series of two-putt pars with a strong finish, rolling in an 11-footer at the 16th before holing from 20 feet at the last.
“I could have got a little impatient, but I felt like my patience was rewarded there with birdies on two of the last three holes,” he said.
“It was really nice to finish like that. As I said, a nice bit of momentum going into the morning round tomorrow.”
It’s the second time in a row he’s opened with a 65 in the US Open and he was pleased to make another strong start.
“It’s been good,” he said.. I went through a run there for a while where my starts at major championships weren’t very good.
“Probably got myself a little too worked up at the start of the week.
“But yeah, even back to the PGA, I opened with a five-under there at Valhalla. Felt like I played okay.
“First day at Augusta, even going all the way back to this tournament last year, opened with a low one.
Wasn’t quite as low as Rickie and Xander (who shot 62), but it was nice to open up with a low one and feel like you’re right in the tournament from the first day.”
McIlroy looked inspired and sharp alongside world No. 1 Scheffler and world No. 2 Schauffele, who scrambled to card respective rounds of 71 and 70.
“I enjoy playing in these groups,” he said. “When you’ve been out here for, whatever it is, 16 or 17 years, sometimes you need a little extra to get the juices going, and being in a group like that definitely helps.”
Scheffler hit just six fairways but his 71 left him tied for 34th with Seamus Power, who battled back from three-over after 11 holes.
“I didn’t hit it, chip it or putt it very well but other than that, I played pretty good,” Scheffler said with more than a hint of irony.
As for Shane Lowry, he rounded off a tough day on a positive by making a 30-footer for birdie at the 18th to shoot 74 and tie for 88th with debutant Tom McKibbin on four-over.
The Clara man missed ten greens in regulation and was five-over after 12 holes before he steadied the ship coming down the stretch as birdies at the 14th and 18th cancelled out his lone three-putt of the day at the 17th.