As potential momentum stoppers go, a double-bogey from the middle of the fairway would crush most spirits. Not Rory McIlroy. The world number one – who floated into Valhalla Golf Club on a feel-good ship of back-to-back wins – responded to such a cardinal sin as if he were merely teasing other pretenders to the throne in this 96th US PGA Championship.

So it was that, after running up a seven on the Par 5 10th and dropping a further shot on the short 11th, the 25-year-old Northern Irishman’s response was to reel off four successive birdies – from the 12th to the 15th – in shooting an opening round 66 , five-under-par, which made his name an ominous presence on the leaderboards positioned around the course.

As a three-way tie developed with Lee Westwood, Kevin Chappell and Ryan Palmer all sharing the first round lead after rounds of six-under-par 65s, McIlroy – winner of a third career Major when capturing the British Open last month and then adding the Bridgestone Invitational to his CV last weekend – used his indiscretion on the 10th, where he had a fairway wood in hand for his approach shot, as a wake-up call to push on.

“”I double crossed it. I was trying to hit it up the left side with a cut, and just double crossed it. You know, it is one of those things that just takes you by surprise, because in a way I haven’t hit a shot like that for a while . . . it sort of knocked me off track a little bit because it was one of the only bad shots I’ve hit in the last few weeks,” said McIlroy of the approach on the 10th, which forced him to reload.

“Walking onto the 12th tee I was muttering a few things to myself but it was just great to hit that second shot in close, in the way I did, as it is one of the toughest par fours on the course and make birdie that made me feel a little bit better. And after what happened at 10 and 11 you have to take whatever you are feeling inside and turn it into a positive because I was ‘hot’ and it was trying to use that fire as a fuel to propel yourself forward.

“So it was great and it shows where my game is at the moment as I was able to do that. Also one of the big things for me in Major Championships is to get off to a good starts and if you look at my three wins in the Majors I have always got off to a good start and it was important to do that.”

His birdies arrived with a torrent, starting with a majestic approach to five feet on the 12th. There followed another crisply struck iron approach to the 13th to six feet, a 30-footer on the 14th and a five-footer on the 15th. The putter finally deserted him on the 16th, where his 12-footer to extend the sequence burnt the hole. But the recovery had been fashioned, and he was back at the business end of matters in the quest for the Wanamaker Trophy.

Likewise, Shane Lowry – who has moved onto a new level of expectations in recent months – confirmed his intent. The 27-year-old Offalyman, who started on the 10th, had what he termed a “shaky start” as he sought to get comfortable. Once he got going, he proved to be very much at home with a hat-trick of birdies around the turn from the 17th to the first. He had another birdie chance on the second, from just two feet, but contrived to miss the cup.

Undaunted, Lowry , who has adopted the habit of wearing mismatched socks acquired in a local Dick’s Sporting store, showed his fighting qualities by holing a 15-footer for par on the third. “I felt really comfortable after that, played decent from there on in,” admitted Lowry, who opened with a 68, three-under.

Lowry’s recent form, although not as spectacular as McIlroy’s, has brought him to these championships with a greater level of expectations. “That’s the way I feel as a player now, that I want to come to these tournaments and compete. I am where I want to be, only three off the lead . . . when you are playing good, you try not to think about it, you just want to keep it going and don the best you can. I’m driving the l well, so I just need to get out there and make as many birdies as I can,” he said.

On a day when cloud cover kept the temperatures in the low 80s Fahrenheit, quite bearable in the circumstances, the course – even with some testing pin locations – proved favourable for decent scoring. There were exceptions – rare ones, with two-time Major champion Angel Cabrera struggling to an opening 82 – but, in the main, players were rewarded with scoring opportunities to receptive greens.

Unfortunately for Tom Watson, his woes as US Ryder Cup captain continued. Matt Kuchar withdrew from the championship before his scheduled tee-time with a back injury, and defending champion Jason Dufner left early after bulging discs in his neck forced his withdrawal after 11 holes. “I’m just not able to play golf right now, it is just pointless,” said Dufner, who had an eight on the 10th to fall to eight-over.

A forgotten man of sorts, Westwood – competing in his 67th Major but yet to savour the glory of success – resurfaced in yesterday’s opening round. One small step, but an important one. In shooting an opening round 65, six-under-par, the Englishman put down a marker: his desire, fuelled by rigorous gym workouts, is as strong as it ever has been.

What made Westwood’s score all the more remarkable is that he suffered a double-bogey six at the first hole, his 10th of the day, which threatened to derail his round. There, his tee shot finished in a plugged lie in a divot in the fairway and he caught his approach heavy and one error was compounded by another.

Westwood’s response was admirable, as he picked up a birdie on the fourth and then ran off four successive birdies from the sixth. His 35-footer on the ninth – after finding another divot in the fairway and then punching a 9-iron approach – was the icing on the cake.

In following up his final round 63 at Firestone with an opening 65 here, Westwood – who missed the cuts at the US Open and British Open – adopted a sensible approach in the days running up to the championship with a limited practise schedule. “Played nine holes each day, didn’t want to drain myself, especially with this heat,” explained Westwood.

More importantly, the frustration which has followed him through the summer wasn’t allowed to boiling point. “I’m not a patient person and I get frustrated really quickly when I know I can play better than I am actually doing. That’s where a good caddie (Billy Foster) comes in, sort of talks to you calmly and says, ‘just keep doing what you are doing and it will come’. I hate hearing those words from him. But he’s right.”

Westwood was among a trio on six-under, all of whom will have noted the presence– a shot back – of McIlroy.