The world’s top two Scottie Scheffler and Rory McIlroy found Oakmont Country Club a bruising challenge on a first day at the US Open when only 10 of the 156 players ended under par.
Masters champion McIlroy had started well and was two under after nine holes, but then unravelled with four bogeys and a double bogey as he posted a four-over 74.
Scheffler, who came into the third major of the year as overwhelming favourite on the back of winning three of his past four tournaments, is three over par after an uncharacteristically ragged round that featured five bogeys.
“I made some silly mistakes and I just need to be a little sharper,” said the American who won last month’s US PGA Championship to add to his two Masters victories.
Out in front on four under is JJ Spaun, who McIlroy beat in a play-off to win The Players Championship in March. The American had four birdies in his opening eight holes and his was the only bogey-free round despite the benign conditions.
He was briefly overhauled by Im Sung-jae, only for the South Korean to bogey three of his final seven holes and drop back.
South Africa’s Thriston Lawrence is one behind Spaun on the notoriously difficult Pennsylvania course, which is hosting a record-extending 10th US Open.
Brooks Koepka, the 2017 and 2018 champion, is alongside Im and Kim Si-woo at two under after birdieing his final two holes to post a 68.
Scotland’s Robert MacIntyre was delighted with his level-par round of 70 as he ranked it “in the top 10 that I’ve played”.
Talking to BBC Sport, he added: “I’ve never played a golf course as hard. Every shot is on a knife edge.”
Former winners Jon Rahm and Jordan Spieth also impressed in their one-under and level par rounds respectively while defending champion Bryson DeChambeau described it as a “brutal test” after posting a three-over 73.
Also at three over is Patrick Reed who made only the fourth albatross in US Open history when he holed his second shot, from 286 yards, at the par-five fourth to pick up three shots.
Sadly for the American, a triple-bogey seven at the last left him three over par for the tournament.
And with dry weather forecast for Friday, this behemoth of a golf course should only get tougher.