Canada’s Adam Hadwin leads the pack at the US Open after day 1 with tournament favorite Rory McIlroy among the five-man group sitting one shot back.

Phil Mickelson of the infamous LIV Golf struggled mightily a week out from his participation in the league’s first event. The American shot eight-over par 78 to sit near the bottom of the 156-player field at The Country Club.

The long-time fan favorite bogeyed three of his first five holes and then made a double-bogey at the par-three sixth where he four-putted from 12 feet. The 52-year-old added another double-bogey at the 12th hole before closing another bogey on a day when his latest bid for the career Grand Slam effectively came to an end.

McIlroy, who came into the year’s third major fresh off a successful title defense in Canada, shot a three-under-par 67 and maintained a clean scorecard until a bogey at the final hole

That left Northern Ireland’s McIlroy level with Englishman Callum Tarren, Swede David Lingmerth, American Joel Dahmen, and South Africa’s MJ Daffue.

But the first day of the US Open belonged to Adam Hadwin, who has never finished better than 24th in his 19 major championship appearances.

He carded five birdies over a sizzling six-hole stretch on the front nine to surge up the leaderboard.

Hadwin, who has one PGA Tour win to his name, showed plenty of poise the rest of the way and coolly offset a bogey at the 12th with a birdie at the following en route to a 66 that marked his lowest score in 63 career rounds in major championships.

Among a pack of seven golfers sitting two shots off the pace was former world number one and 2016 U.S. Open champion Dustin Johnson, another defector to the LIV league.

Defending champion and world number two Jon Rahm was level with PGA Championship winner Justin Thomas and among a group who are sitting three shots back of Hadwin.