Tiger Woods dug himself an early hole with two double-bogeys on his first nine at the US PGA Championship and hit the turn on three over as Brooks Koepka moved into a share of the lead at Bethpage Black.

Making his first competitive start since winning the Masters in April, Woods - starting at the 10th hole with Koepka and Francesco Molinari - found the right rough with his first tee shot and learned early on that recent frequent rain on Long Island, New York, was going to make the rough particularly punishing on an already tough course.

He was forced to hack out, then knocked a third-shot approach over the back of the green and missed a four-foot putt for bogey coming back.

Just like that, he was two over a hole into the year's second major, which defending champion Koepka led along with Tommy Fleetwood on four under through 10 and 13 holes respectively.

Woods was able to steady himself with pars over the next four holes before cashing in his first good look at birdie on the par-four 15th hole by rolling in a 15-footer breaking left to right.

He avoided giving that shot right back on 16, again forced to merely put the back in the fairway after an errant drive but then nearly holing out on his third shot and then saving par with a short putt.

However, the American found a bunker on the 199-yard par-three 14th and had to blast out from an awkward stance, but compounded his problems by being over-aggressive with his par putt. After running the putt some 10 feet past the hole, he missed his bogey putt coming back.

A good approach to 20 feet on 18 was not rewarded as Woods missed the birdie putt and made the turn at three over, but he birdied the next two holes to regain some momentum.

Koepka opened with a birdie and added two more - at the par-three 14th, rolling in a 20-footer, and another at 18 - to make the turn at three under.

World number three Koepka birdied his 10th hole of the day to take a sole lead at four under before Englishman Fleetwood moved alongside him with a fifth birdie of the day.