Miguel Angel Jimenez and Keegan Bradley were involved in a remarkable row during the third day of the WGC-Cadillac Match Play in San Francisco.
Neither player could qualify for the last 16 at Harding Park after losing their first two group games, but that did not stop them almost coming to blows during their dead rubber.
Jimenez appeared to disagree with where Bradley had taken a drop on the 18th and, while trying to put his point across to a rules official, told Bradley's caddie Steve Hale to shut up.
Hale took exception to this and Bradley - who had already asked Jimenez to "do me a favour" and walk over to his own ball - then stepped right in front of the Spaniard to say "Don't tell my caddie to shut up."
The issue was finally resolved and Jimenez won the match, but although he and Bradley shook hands, the debate was still raging and Hale refused to shake hands with Jimenez on the 18th green.
"We didn't do much talking after the round. I have nothing but respect for him. He's a great player out here but I have to be able to stick up for myself," Bradley told reporters afterwards.
"It was just a heat-of-the-moment thing.
"It was disappointing. I'm pretty bummed out about it. It was just ... I had a ruling and he felt like he needed to intervene and I felt like he was being inappropriate to me and my caddie.
Jimenez was keen to move on from the argument.
"Whatever he say, now is finished," he said. "The round is finished and everything is done. We had a little discussion, but it is done."