Rory McIlroy, looking to snap a 10-year major drought, capped a flawless outing with a birdie to join Patrick Cantlay atop the first-round US Open leaderboard at Pinehurst Resort in North Carolina.
World number three McIlroy, in hot pursuit of an elusive fifth major title, closed his bogey-free round with a 19-foot birdie putt for a five-under-par 65 that left him and Cantlay one shot clear of Swedish sensation Ludvig Aberg.
Bryson DeChambeau, who was one shot shy of forcing a playoff with Xander Schauffele at last month's PGA Championship, was a further shot back with Frenchman Matthieu Pavon, who became the first player with two eagles in a US Open round at Pinehurst.
New Zealand's Ryan Fox is tied for 65th after an opening round three over par 73.
McIlroy showcased incredible distance control and a silky touch with his short game and took advantage of both par-fives, including at the fifth hole where he chipped in from 66 feet with his third shot.
The Northern Irishman got to within a shot of Cantlay with a birdie from 11 feet at the par-four 16th, nearly drew level at the par-three 17th where his birdie putt stopped just short of the hole before cashing in at the par-four 18th.
"I felt like I controlled most aspects of my game really well," said McIlroy, whose last major triumph came at the PGA Championship in August 2014. "Controlled myself, my mind and was very disciplined when I needed to be."
Cantlay, in pursuit of his maiden major, went out early and produced a sizzling burst of late birdies to set the pace on a tricky Pinehurst No. 2 layout where only a handful of golfers were able to break par.
Cantlay, competing in his 30th major, started on the back nine and kick-started his day at the par-four 11th, his second, where he chipped in for birdie from a greenside bunker.
He made the turn at one under but covered his final nine holes in a stunning four-under 31 and had a chance to go even lower but a birdie putt from 19 feet at his final hole shaved the right edge.
"Played pretty solid most of the way," said Cantlay, who needed only 23 putts on the notoriously challenging turtle-shell greens that are one of the course's greatest defence.
"I thought the golf course played pretty difficult. But drove it well. A lot of balls on the fairway. Left the ball in the right spots, for the most part."
'Very proud'
DeChambeau, the 2020 US Open champion and one of 12 LIV Golf players in the field, carded his lone bogey at his 16th hole, the par-four seventh, to slip back before a pair of routine pars top end his day.
Masters champion Scottie Scheffler, who has been lights out this year while racking up five wins, entered the year's third major as the clear favourite but struggled with his accuracy off the tee and on the greens as he opened with a 71.
Playing in a high-profile group with McIlroy and Schauffele (70), world number one Scheffler made a pair of early bogeys and was never able to get anything going after that.
Tony Finau and Tyrrell Hatton were both three shots back of the co-leaders while Spaniard Sergio Garcia was among a large group sitting a further shot adrift.
Garcia, who only learned on Monday that he was added to the field as an alternate, made the most of his opportunity by carding only the sixth bogey-free round in US Open history at Pinehurst No. 2 .
"Obviously to shoot under par in a US Open, which is a championship that I love, it's always great," said Garcia. "To go bogey-free is even greater. It's something that I give a lot of respect to, and I'm very proud of."
Struggling Woods
Defending champion Wyndham Clark, eager to jump-start a season in which he has missed the cut at the first two majors, went out late and opened with a 73.
The opening round of the US Open was played under sunny skies and on a layout that will test the mental discipline of the players all week given its tricky greens and fairways that bleed into sandy waste areas full of wire grass.
Tiger Woods, competing in only his fourth event of the year and who accepted a special exemption to play in the U.S. Open, enjoyed an encouraging start but his putter abandoned him as the round wore on and he opened with a 74.
"I didn't hit my irons particularly well," said Woods, who was one under through six holes before carding five bogeys over a seven-hole stretch around the turn.
"Didn't putt that great. Drove it on the string all day. Unfortunately I just didn't capitalise on it."
Phil Mickelson, US Open runner-up a record six times, saw his hopes of completing the career Grand Slam of golf's four majors fade with a 79 in a round that started with four consecutive bogeys.
-Reuters