Bryson DeChambeau came for Brooks Koepka's abs and the world number one did not let him get away unscathed.
Koepka is regarded as the most muscular player in golf but DeChambeau, a five-time winner on the PGA Tour, aimed a dig at his physique, which was laid bare in ESPN magazine's Body Issue last year.
DeChambeau, a Southern Methodist University graduate majoring in physics, has been working with a muscle activation specialist and spoken of his desire to become "massive".
When asked about Koepka's conditioning on his Twitch stream, DeChambeau said: "I don't know if his genetics even make him look good, to be honest. I mean [in] the Body Issue he didn't have any abs, I'll tell you that. I got some abs."
Unsurprisingly it did not take too long for the four-time major champion to fire back with a stinging barb.
Alongside a photo of the trophies from his triumphs at two US PGA Championships and two U.S. Opens uploaded to Twitter, he wrote: "You were right @b_dechambeau I am 2 short of a 6 pack!"
DeChambeau's best performance at a major was coming tied-15th at the 2016 U.S. Open.
English golfer Eddie Pepperell was impressed by Koepka's comeback and summed up the exchange nicely.
"This is why you just don't go after the No.1 golfer in the world. Christ," world number 55 Pepperell tweeted.