For a couple of decades, the often frosty Tiger Woods v Phil Mickelson rivalry has defined a golfing generation - but that mantle has now been well and truly passed.
During an interview at this week's PGA Championship, rising superstar Brooks Koepka could not hide his disdain for fellow American Bryson DeChambeau, as their paths crossed at South Carolina's Kiwah course.
Asked to reflect on his third round by the Golf Channel, Koepka had to stop mid-answer and rolled his eyes, as DeChambeau passed behind him and commented on a question about his putting performance.
Koepka had just badly misread putts on the 17th and 18th greens, as eventual winner Phil Mickelson took an overnight lead into the final day.
Some social media viewers suggest DeChambeau's comment was along the lines of "just got to start it on the right line".
"I lost my train of thought, hearing that bullshit," Koepka told interviewer Todd Lewis.
"F**king Christ," he muttered, before resuming the interview.
The pair are two of the brightest of golf's current wave of stars, with Koepka falling two strokes short of his fifth Major title and DeChambeau threatening to rewrite the game's rule books with his high-octane power game.
Their feud appears to have begun two years ago, when Koepka publicly criticised DeChambeau's notoriously slow playing style.
After Koepka lost 9kg for an ESPN magazine 'body issue' spread, DeChambeau took a shot at his physique.
"I don’t know if his genetics even make him look good, to be honest," he said. "I mean, the Body Issue, he didn’t have any abs, I can tell you that.
"I’ve got some abs."
Koepka responded with a tweet picturing his four Major trophies, claiming he was "two short of a six-pack".
Last year, DeChambeau protested to a rules official, after his ball landed next to an ant hill and the conversation went viral. The next day, Koepka mocked the exchange, joking with his caddie that an ant was crawling on his ball.
Now, all eyes will turn to next month's US Open - a tournament Koepka has won twice - with the hope that they will be drawn in the same playing group.
US captain Steve Stricker may want to keep them seperated for the Ryder Cup match against Europe in September.
