Early last year, American duo Brooks Koepka and Bryson DeChambeau got into a spat on social media - and, judging by events at last weekend's PGA Championship, bad blood still very much exists between the pair.Their feud kicked off when DeChambeau took a verbal shot at Koepka's physique during a January 2020 Twitch stream.Koepka had recently appeared naked on the front cover of The Body Issue of ESPN magazine, but DeChambeau was far from impressed.Bryson told his followers: "I don't know if his genetics even make him (Koepka) look good, to be honest. I mean, the Body Issue, he didn't have any abs, I can tell you that. I've got some abs."Koepka then fired back on Twitter, uploading a photo of his four Major trophies, goading DeChambeau with the comment: "2 short of a 6 pack!".Koepka has also publically criticised DeChambeau in the past for his slow style of play.Things obviously got very heated between the pair in a short space of time. However, like most social media quarrels, the world assumed that the issues between Koepka and DeChambeau had simply been a storm in a teacup and that the matter had been resolved in private.Nothing, it seems, could be further from the truth.Amazing footage has leaked out from a post-round interview conducted by the Golf Channel during the PGA Championship, which saw Koepka struggling to keep his composure at the mere sight of DeChambeau off-camera.The clip, which is now doing the rounds on social media, shows Koepka clearly distracted even before the interview begins. The 31-year old rolls his eyes as soon as he catches a glimpse of someone out of shot - and is obviously agitated throughout the interview.

Koepka managed to focus himself enough to start answering some questions. However, this focus is broken in spectacular style when DeChambeau walks directly behind him with a member of his team.

At this point, DeChambeau appears to tell Koepka that he "just needs to start it on the right line," in reference to some of his rival's wayward putts during a windy day's play at Kiawah Island.

It is fortunate that the interview was not going out live - because DeChambeau's comment absolutely enrages Koepka - to the point where the interview has to be terminated.

"I f***ing lost my train of my thought hearing that bull****. F***ing c*****," exclaims Koepka. 

When the interviewer points out that staff at the Golf Channel will probably enjoy the crazy outtake later, Koepka is still absolutely furious.

"I honestly wouldn't even care," he responds.

Well, as it turns out, the whole world can now witness the incredible exchange. This year's PGA Championship runner-up will not be going out for dinner with DeChambeau any time soon.