Canada's Adam Hadwin fired a four-under par 66 to seize a one-stroke lead late in Thursday's first round of the US Open.
Hadwin birdied five of the last six holes on the front nine to seize the lead and held on over the back nine with one birdie, one bogey and seven pars.
Hadwin missed a six-foot par putt to bogey the third hole, then birdied five of the next six, dropping his approaches between two and four feet on all but the par-3 sixth and making each short birdie opportunity to grab the outright lead at 4-under.
He stayed in front with a clutch five-foot par putt at the 10th and answered a bogey at the 12th with a birdie at 13 then parred in.
The only US PGA Tour title for Hadwin came at the 2017 Valspar Championship. His best finish in 19 prior majors was a share of 24th at the 2018 Masters.
Hadwin, 34, sat one stroke ahead of four-time major winner Rory McIlroy of Northern Ireland, Sweden's David Lingmerth, American Joel Dahmen, England's Callum Tarren and South African M.J. Daffue.