Rory McIlroy was involved in an altercation as tensions boiled over after a dramatic day at the Ryder Cup.
The bust-up followed an incident on the 18th green, where Team USA’s Patrick Cantlay had putted a birdie.
There were jubilant scenes as Cantlay’s caddie Joe LaCava waved a cap over his head to celebrate.
McIlroy had asked the caddie to move out of his eyeline so he could putt, but LaCava initially refused to do so. He went on to miss.
The drama spilled over to the car park outside the clubhouse, where McIlroy was seen pointing and shouting.
Fellow European player Shane Lowry intervened to pull McIlroy away and towards a waiting car to leave the course.
Europe captain Luke Donald later revealed that McIlroy had “felt the line was crossed”.
He explained: “There was some hat-waving going on throughout the day from the crowd, not our players.
“I talked to Rory and he politely asked Joe to move aside as he was in his line of vision, he stood there and didn’t move for a while and continued to wave the hat and I think Rory was upset about that.
“The Ryder Cup is always passionate. We’ve seen that many times over the past.”
McIlroy later said: “They played a great match, and yeah, I mean, a few scenes there on 18 and just fuel for the fire.”
Cantlay had been taunted by European fans all afternoon after it was reported that he was refusing to wear a Team USA cap in protest at players not being paid to compete in the Ryder Cup.
Europe need just four points from the final day’s 12 single matches to complete their revenge mission in Rome and regain the Ryder Cup.
Earlier on Saturday, Team USA’s Scottie Scheffler – the world’s number one golfer – broke down in tears after he and his partner suffered a historic defeat.
In a tournament famous for close finishes, there were still seven holes left to play when the Europeans sealed victory – the largest margin ever seen in the event’s history.
Scheffler was comforted by his wife Meredith as the enormity of the loss sank in.
While the 27-year-old had wanted to try and make amends in the afternoon, he was left out by US captain Zach Johnson.