Brooks Koepka accused Jon Rahm of acting like a child after the Spaniard’s stunning afternoon performance at the Ryder Cup in Rome on Friday.
Rahm eagled two of the final three holes at Marco Simone as he and Nicolai Hojgaard came from behind to halve their fourballs match against Koepka and Scottie Scheffler.
The 28-year-old world number three, who chipped in three times in his two matches during the day, celebrated exuberantly as Europe took firm command of the contest, leading 6.5-1.5 after day one.
It was not clear, however, what Rahm did in particular to rile the American.
Koepka said in a TV interview: "I think me and Scottie birdied 14, 15, 16, 17, 18, and then ‘lost’ (to) two (eagles).
"So yes, I mean I want to hit a board and pout just like Jon Rahm did but, you know, it is what it is. Act like a child. But we’re adults. We move on."
Koepka alluded to this subject again when asked what the US needed to do on Saturday to get themselves back into the match.
He said: "Honestly, we’ll be fine. We’re all grown-ups, we act like grown-ups. We’ll be just fine. Just got to play and see where it puts you.
"Just keep fighting. You never know what’s going to happen. (We have) still got a long day tomorrow.
"I guess it’s just a matter of momentum, but we’ve got to go out in the first session and play well, that’s for sure."
Europe captain Luke Donald was asked about Rahm’s comments but did not offer an opinion.
"I certainly didn’t see any of that," Donald said. "Jon was a big support system for Nicolai today. Jon’s a passionate person, but I didn’t see him acting any other way."
United States skipper Zach Johnson was also unable to elaborate on Koepka’s remarks.
He said: "I don’t know what that is referring to to. I am sure Brooks is frustrated like all 18 of us are with today and the result."
Johnson, meanwhile, insisted that he was proud of his players and "our time is coming" after Europe opened up a record-equalling five-point lead.
"I am proud of the way they have gone about their business, the way they came out (after the foursomes)," said the American captain, who revealed they were battling minor illness within the camp.
"I'm extremely proud of their fight and their character. I think when you have adversity and when you have challenge you can kind of go one of two ways, and they decided to do it with class and character.
"From my vantage it looks like the European team executed golf shots a little bit better than we did today, and that’s golf, so you tip the cap to Luke (Donald) and his team."
Johnson was reluctant to go into details about the specifics of the illness affecting his team but when pressed on the matter he admitted it had impacted some of his decision-making.
"We have contingencies and things of that nature based on a lot of things," he said.
"I would say that we’d love to have everything drawn out way ahead of time but there’s certain things you cannot control and we are trying to control the controllables in our team room, and I’ll leave it at that.
"There’s been some unforeseen things that we’ve had to navigate around, which is really unfortunate, in the sense of health.
"It’s not an excuse because we have depth but I’ll just say I’m grateful we have a team doctor.
"It’s kind of passed around a little bit, caddies, players. It is what it is. But it’s nothing more than that. Guys are fighting and playing regardless.
"We have got some congestion and some just signs of things that are unfortunate.
"It’s one of those where sometimes the energy is probably a little low, but the ability and desire to go out and play is still there. It has spread through my team."
