US Open golf champion Rory McIlroy refused to back down in his Twitter spat with broadcaster Jay Townsend after safely making the cut in the Irish Open.
Northern Irishman McIlroy explained why he had responded so acerbically to Townsend's criticism of McIlroy's "shocking" course management.
Townsend's comments on Twitter - the American had endorsed a tweet that McIlroy should employ Steve Williams, Tiger Woods's former bagman, to help his course management - were interpreted by McIlroy as another attack on his caddie, Irishman JP Fitzgerald.
The Ulsterman said that is why he had finally snapped and told Townsend to "shut up" in a subsequent tweet response. It was one comment too far and the 22-year-old says he has to stand up for his caddie.
McIlroy says Fitzgerald is one of his closest friends and he's had to deal with it for three years and not really say anything. He says Townsend was just keeping on at Fitzgerald and he felt he just had to say something, as Fitzgerald has taken him from 200th in the world to major champion and fourth in the world.
Townsend had tweeted: "McIlroy's course management was shocking. Some of the worst course management I have ever seen beyond under-10 boys' golf competition."
McIlroy quickly replied: "Shut up ... you're a commentator and a failed golfer, your opinion means nothing!"
While McIlroy had his say on Saturday, Townsend decided not take the argument further, calling it an unfortunate exchange that he prefers to put in the past.