The Ryder Cup sparked uproariously into life as tempers flared and Shane Lowry had to hold Rory McIlroy back as he confronted US caddie Jim "Bones" Mackay and poked him in the chest in the car park at Marco Simone in Rome.

McIlroy and Matt Fitzpatrick looked set to clinch a crucial win over Patrick Cantlay and US Open champion Wyndham Clark to tie the afternoon foursomes session at 2-2 and give Europe a seven-point lead.

But after Cantlay transformed himself from pantomime villain into all American hero by holing with three sensational putts on the last three greens to win the match one-up, all hell broke loose as the Americans reduced the deficit to just five points — 10.5-5.5.

Cantlay, who was reportedly at the centre of US locker room dissent and refusing to wear a cap over Ryder Cup pay, made an outrageous 43-footer, sparking wild celebrations by the entire US team and his caddie Joe LaCava.

McIlroy still had a 30-footer to halve the match but Cantlay’s caddie LaCava was still celebrating on McIlroy’s line and there was a fiery exchange as Lowry and Justin Rose took umbrage, telling LaCava to get out of McIlroy’s way.

After Fitzpatrick also missed his putt to halve the match, McIlroy and LaCava had a face-to-face confrontation that spilled over into the car park, where he appeared to lose his temper with Justin Thomas’ caddie MacKay.

Lowry had to step in a separate McIlroy and Mackay but as he bundled the Holywood star into his courtesy car, the Ulsterman said: “This can’t happen, this can’t happen, it’s a f*****g disgrace.”

Cantlay had been mocked by European fans, who doffed their caps to him all afternoon after a tweet by Sky Sports Golf reporter Jamie Weir reported that the American he’d refused to wear a cap in protest at the lack of pay for Ryder Cup play and had been a disruptive figure in the team room.

The US players, caddies and vice-captains celebrated his putt by ironically waving their caps while Cantlay doffed an imaginary one to the crowd.

European skipper Luke Donald addressed the issue afterwards and backed McIlroy’s teammates for defending him.

“Yeah, obviously I was there on 18,” Donald said. “I saw it unfold when Patrick made that putt, Joe was waving his hat. Obviously there was some hat-waving going on throughout the day from the crowd for our players.

“Talked to Rory. He politely asked Joe to move aside. He was in his line of vision. He stood there and didn't move for a while and continued to wave the hat, so I think Rory was upset about that.”

Asked about the car park incident, Donald added: “Listen, I'll talk with Rory when I get back. I didn't see the incident personally. I saw the one on 18. As I said in my speech, we always try and play with passion, play with energy, but play with respect. That will certainly be my message to the players.

“We all want to win, but we want to do it in the right way. You know, from what Rory told me, he did ask Joe to move. He took a long time to move. It was a little off-putting because he still had to putt. And so Rory got upset, and I understand that.”

Cantlay refused to answer a question in his post-match press conference asking if he wanted to be paid.
“It’s not about that,” he said. “It's just about Team USA and representing our country. That's all I've got to say about that.”

As for his refusal to wear a hat, he said: “The hat doesn't fit. It didn't fit at Whistling Straits, and didn't fit this week. Everyone knows that.”

The US will need to produce the biggest Ryder Cup comeback of all time to win given Europe were only four points behind at Medinah in 2012 and the US were also four back at Brookline in 1999 before storming back to win.

“Hopefully have a ray of light and we can build on this session and try and pull off a big victory tomorrow,” Cantlay said.

But Donald is confident in his troops and their five point lead.

“Listen, we are in a great position, five points ahead going into the singles at home,” he said. “I like where we are. I like the feelings in the locker room.  “Patrick obviously made some great putts and flipped that match at the end but to be honest, we've had a lot of momentum going our way, so we are in a good position.”