Ruud originally said in a recent interview that he's an idiot on court and that he was happy to just get 90 points and 50,000 in prize money.
“I don’t know, he was totally crazy when I played him.” Ruud said during a recent interview with Swedish website Tennisportalen.
“It was nice to win. If I celebrated after the match or not? I don’t care. I was happy I got 90 points and 50 000 dollars in prize money so why wouldn’t I celebrate? It’s his problem that he’s an idiot on court.”
Kyrgios replied saying that next time he has something to say about him, he would appreciate if he did it to his face and that he'd rather watch paint dry than watch him play tennis.
He added that he'd never heard of him before and that he understands why he has to run his mouth if no-one has ever heard of him.
“Hey @CasperRuud98 next time you have something to say, I would appreciate you say it to my face,” he wrote.
“I’m sure you wouldn’t run your mouth so much after that. Until then I will continue to rather watch paint dry (than) watch you play tennis, boring AF.”
In a second tweet, Kyrgios seemingly poked fun at Ruud’s popularity in the sport. Going on to retweet one comment which reads ‘Genuinely never heard of the guy until now.’
“But again, I also understand why you have to keep my name in your mouth, because people don’t even realise that you play tennis.” He continued.
“Goodluck in Milan (Next Gen Finals) champ x.