Lowry

After starting with four pars, Lowry – who is without an individual victory since September 2022 – carded back-to-back birdies at the fifth and sixth holes.

The former Open champion vaulted into a share of the lead with a run of five straight birdies from the par-four 11th before picking up a shot at the last to edge ahead of Nakajima.

“It’s not that hard when you hit it in play out there, but you start missing fairways it becomes quite tricky, so I’m happy with that,” said Lowry.

He added: “You need to shape it around the course, hit it in position off the tee and it’s all about your iron play. That’s one of my strengths and I took advantage of that today and managed to roll a few putts in on the back nine, which was nice.”

Lowry added there was a “little bit” of Ryder Cup chat with playing partners Fleetwood and Donald.

“We could hear the horns from the road, it was not as off-putting as the Bethpage [Black] crowd,” he said with a smile, referring to the hostile New York fans at last month’s Ryder Cup.

Fleetwood mixed four birdies, an eagle and two bogeys to sit four shots back.

Donald, who is playing his first tournament since his second Ryder Cup success as captain, carded five birdies and a bogey to match fellow Englishman Fleetwood and 2023 Open champion Brian Harman.

Playing with McIlroy, US Ryder Cup player Ben Griffin opened with a 68 while McIlroy’s European team-mate Viktor Hovland signed for a 71.

But the exchange set the tone of the day. McIlroy lost his cool towards the end of his morning foursomes win alongside Lowry, swearing at American fans during a heated moment on the 16th fairway.

With some members of the crowd fuelled by all-day drinking, things became more heated in the afternoon fourballs.

The atmosphere simmered over the opening few holes before becoming a tinderbox on the par-five fourth green.

McIlroy backed off a putt for an eagle three after a shout disrupted his concentration. He missed his effort but Lowry holed his chance – and then erupted with a passionate and pointed celebration towards the offender.

When Lowry stuck away another putt for a birdie on the fifth, he let rip with another vocal celebration. Only his dad Brendan, watching from the side, shouted louder.

Things ignited again on the sixth green when McIlroy backed off another putt. “Can’t take it, Rory?'” bawled one New Yorker.

A crowd in a city known for its brash and harsh sports fans clearly felt this was all fair game.

By this stage, the exasperated European pair – as well as vice-captain Eduardo Molinari – were pointing out offenders to the police officers, who had visibly moved in tighter in a bid to calm the mood.

American opponents Justin Thomas and Cameron Young sensibly appealed for calm, but also stoked emotions with wild celebrations when they won holes seven and nine to leave a tense match all square again.

Messages warning fans of a zero tolerance approach to abusive shouting flashed up on huge screens across the course, saying they would “continue to closely monitor fan behaviour and take appropriate action”.

Shortly after Lowry lunged towards the fan on the 10th tee, one of these reminders was booed by the American fans around the 11th green.

The PGA of America, who organise the Ryder Cup, had already beefed up security around all four matches by this point and the sight of police officers trailing the players was a clear warning sign of the threat they faced.

On Thursday, some players at Quail Hollow – including world number one Scottie Scheffler – complained about mud balls, where golf balls get covered in mud and dirt during bad weather.

Preferred lies – a rule sometimes used during periods of adverse weather that permits players to lift, clean and place their ball within a specified distance of its original position on closely-mown areas – were not sanctioned for use by the PGA of America.

Lowry’s tee shot on the eighth hole pitched on the fairway and bounced sideways into a divot left by another player, which meant he was not allowed the relief for an embedded ball that would have applied had it been in his own pitch mark.

“You hit a lovely tee shot, you’re not expecting that,” said world number 10 Lowry.

“I was obviously very annoyed with that because I felt like I had quite a bit of momentum going in the round, and standing there with 40 or 50 yards to the pin off the fairway it’s an easy pitch shot for me – and I walk away making bogey.”

Lowry was particularly unhappy with the unsolicited input of an on-course reporter, adding: “The ESPN guy was a bit too involved when he wasn’t asked to be and that’s what annoyed me a lot.

“He came straight over and said: ‘That’s not your pitch mark.’ That’s not for you to talk about, it’s for me to call a rules official and decide what happens.

“I wasn’t arguing that it was my pitch mark, I was trying to be 100% sure because imagine if I come in [after the round] and all of a sudden somebody told me that was my pitch mark.

“They told Brooks [Koepka] his ball was OK yesterday and it was on the driving range, so you need to be careful about what you’re doing because there’s so much at stake.”