Jimmy Walker holds a one-shot lead as a host of star names struggled to come to terms with the heat and a testing Baltusrol course on the first day of the PGA Championship.
Walker posted an early five-under 65 and his score was not matched throughout the remainder of the round as conditions became tougher for the afternoon starters and took their toll on the likes of Dustin Johnson, while Rory McIlroy also faces a battle to make the cut after an opening 74.
Martin Kaymer was the only player to threaten Walker’s lead as he matched the earlier 64s of Ross Fisher and Emiliano Grillo, with defending champion Jason Day managing a commendable 68 after his preparations were disrupted by illness earlier in the week.
Henrik Stenson fared best of the traditional major champions group, the Open winner coming home in 33 to close on three under while Masters champion Danny Willett struggled to a 71 and pre-tournament favourite Johnson provided the biggest surprise of the day as he laboured to a 77.
The scoring was significantly better for the early groups, and Walker roared to the top of the leaderboard when, after beginning his tournament at the 10th, he reeled off five birdies in seven holes from the 13th before he blotted his card at the sixth as he pulled his drive into thick rough on the left and could not reach the green in two.
But the Ryder Cup hopeful got the shot straight back with a 30-foot putt for his sixth birdie of the day at the next, and he safely parred his final two holes to stay ahead of Grillo and Fisher, who closed out his 66 with birdies at the final two holes.
Kaymer made it a three-way tie for second when he followed five opening pars with four birdies in a sparkling five-hole stretch from the 15th, and the 2010 champion responded to a bogey at the second with a birdie at the next and parred safely in.
Fisher’s fellow Englishman Andy Sullivan joined American pair Harris English and James Hahn on three under after he birdied three of his last four holes, and Stenson got his fifth birdie putt of the round to drop in the side of the hole at the last to cap his excellent 67.
Day and Rickie Fowler are the stand-out names in a group of a dozen players to open with a 68, although the world No 1 had another up-and-down day on the greens as he mixed three birdies with one three-putt bogey and missed a series of chances to convert some sublime approaches.
Jordan Spieth continued his erratic form and had to scramble hard for pars until coming to grief at the seventh, where a wild drive into the trees on the right led to an ugly double-bogey six.
Last year’s runner-up frequently aired his frustrations after missing a number of fairways, but he dug deep and finished with a flourish as birdies at 16 and 18 salvaged a respectable level-par 70.
Open runner-up Phil Mickelson, the PGA champion the last time it was played at Baltusrol in 2005, was four over after 11 holes before fighting back with three birdies to post a 71, a score emulated by two-time Masters champion Bubba Watson after the left-hander lifted his spirits on a tough day with birdies at 17 and 18 to finish.
But McIlroy failed to make a birdie for only the fourth time in 115 major championship rounds, missing a hatful of chances from inside 12 feet and dropping three shots in four holes early in his round before a three-putt bogey at the second hole summed up his day.
The two-time champion used 35 putts overall and believes he needs “something in the mid 60s” on Friday to have any hope of contending for a third Wanamaker Trophy, but at least he is better placed than Johnson after the US Open winner crashed to seven over par.
Johnson double-bogeyed the third after pulling his drive way left, and he dropped three shots in a row from the fifth before rolling in his only birdie putt of the day at the ninth.
But he ran up another double-bogey at 11 after finding sand off the tee and thinning his escape attempt into the lip of the bunker, and hopes of a final-hole birdie disappeared when another errant drive found the lake.