GUIDONIA MONTECELIO, Italy — Rory McIlroy lost his match at the Ryder Cup. Then he lost his cool.

In scenes sure to stoke tensions ahead of Sunday’s singles, McIlroy accused Patrick Cantlay’s caddie, Joe LaCava, of waving his hat in his line of vision ahead of the European star’s crucial putt on the 18th green in the final fourballs match Saturday.

That incident prompted another angry exchange involving McIlroy as he left the Marco Simone club. McIlroy was seen to be visibly furious outside the clubhouse as Jim “Bones” Mackay, the caddie for Justin Thomas, attempted to intervene.

McIlroy was ushered into a waiting car by European teammate Shane Lowry, but only after plenty of shouting and finger-pointing. It wasn’t immediately clear who McIlroy was aiming his anger toward, but

U.S. captain Zach Johnson said LaCava “was not a part of that.”

The images were soon all over social media and will no doubt be part of the pre-match team talks before the singles. LaCava — like others in the U.S. team — had removed his hat in a playful gesture after Cantlay holed a 45-foot birdie putt in near-darkness on No. 18. Throughout the afternoon, thousands of European fans waved their caps at Cantlay, likely in response to a report on Sky Sports claiming he refused to wear his cap out of protest because he wants to be paid.

European captain Luke Donald said McIlroy “politely asked Joe to move aside.” McIlroy still had a putt for birdie to tie the match, which he wound up missing.

“[LaCava] stood there and didn’t move for a while and continued to wave the hat, so I think Rory was upset about that,” Donald said.

The Associated Press