Corey Conners withstood hammering winds to claim a two-stroke lead following the opening round at the US PGA Championship as Brooks Koepka impressed but Rory McIlroy and Dustin Johnson struggled.

Prior to Thursday's first round in South Carolina, Conners' best position after any round of a major was equal sixth through 54 holes at this year's Masters at Augusta.

Conners bettered that at Kiawah Island Golf Resort, where the Canadian defied the wind to set the early pace with a five-under-par 67.

Without a victory since his solitary PGA Tour triumph at the 2019 Texas Open, Conners was almost flawless in gusty conditions, holing six birdies with just one bogey.

Conners' lead marks his third career 18-hole lead/co-lead on the PGA Tour (0-for-two to date) and first at a major. Earlier this season, the 29-year-old was tied for the first-round lead at the Arnold Palmer Invitational and finished third – his best result of the season.

Koepka ended day one in a share of second position alongside Keegan Bradley, Viktor Hovland, Aaron Wise, Sam Horsfield and Cam Davis.

Koepka has been plagued by injuries since winning back-to-back PGA Championships in 2019 and a fourth major title in three years – the American star underwent knee surgery in March before missing the cut at last month's Masters.

But Koepka impressed on Thursday, overcoming a slow start to shoot a three-under-par 69.

Koepka double-bogeyed his opening hole on the back nine, however, the four-time major champion only dropped one shot after that as he tallied six birdies.

He has opened the PGA Championship with a score in the 60s in each of the last six years, the longest such streak at any major in the modern era (since 1934), eclipsing Jack Nicklaus (five – 1972-1976 Masters).

Defending champion Collin Morikawa is a stroke further back alongside the likes of five-time major winner Phil Mickelson.

Big-hitting American and reigning U.S. Open champion Bryson DeChambeau signed for an even-par 72 at the close of the first round, level with Jon Rahm and Justin Rose, while Masters holder Hideki Matsuyama, former world number one Jordan Spieth – eyeing a career Grand Slam – and Xander Schauffele shot 73s.

Jason Day and Patrick Reed were also further down the leaderboard as two-time PGA Championship winner McIlroy and world number one Johnson were powerless in the wind.

McIlroy – seeking a first major trophy since 2014 – recorded a three-over-par 75, which included six bogeys and just three birdies.

Justin Thomas also went three over for the day, while Johnson finished with two double-bogeys and a bogey in a forgettable four-over-par 76 display.