Koepka said on Wednesday that DeChambeau "went back on" something the two had discussed two years ago.

That came on the heels of Koepka pointing the finger at his rival for causing the rift in an interview with ESPN on Tuesday.

The feud initially began in January 2019 when Koepka criticised the general slow pace of play at the Dubai Desert Classic.

Without naming DeChambeau, it was evident that he was the cause of Koepka's ire.

Later that year, the two had a conversation after DeChambeau approached Koepka's caddie, Ricky Elliott, and said he wanted to talk with Koepka.

The dust appeared to be settled until DeChambeau took a shot at Koepka's abs during a live stream on Twitch early last year.

That led to Koepka firing back on Twitter with some words and a picture of his four major trophies.

And the feud has escalated significantly since Koepka was caught rolling his eyes and dropping a choice word after DeChambeau walked in the background of an interview with the Golf Channel last month that was never aired but leaked.

"If you're going to go back on your word I don't have much respect for that." – Brooks Koepka

The two have traded barbs over social media since as the bickering continues to dominate the golf news cycle.

"I thought it was just interesting when he walked up to my caddie and told Ricky that if I had something to say, to say it to his face," Koepka said Wednesday of the 2019 exchange at The Northern Trust.

"I thought that was kind of odd. Don't walk up to my face, say it to my caddie.

"When we had that conversation we agreed on something and he went back on it.

"So, you know, if you're going to go back on your word I don't have much respect for that."

Both golfers said they were not approached about being paired together at the US Open, and they are again on opposing schedules for the first two rounds this week.

DeChambeau will tee off on the 10th hole early on Thursday with Stewart Cink and Patrick Reed.

Koepka will also tee off on the back nine, but in the afternoon along with Dustin Johnson and Tony Finau.