The pair have been engaged in a feud-of-sorts after clashing at the Rome Masters in May.
Kyrgios was disqualified from a match between the two players after throwing a chair on to the court with the score tied at one-set all.
Ruud celebrated his subsequent victory in a wild manner, riling Kyrgios.
The 20-year-old defended his decision to celebrate in such a way, reigniting the feud with Kyrgios.
“I saw that he wrote a little about it,” Ruud told Tennisportalen.
“Okay, he got disqualified but if we look at the head-to-head between me and Kyrgios it’s 1-0 to me. That means I’ve won against him?
“He can say as much as he wants about me getting disqualified but it still says 1-0 to me. I don’t know, he was totally crazy when I played him.
“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 in prize money so why wouldn’t I celebrate?
“It’s his problem that he’s an idiot on court.’
Kyrgios, 24, has now hit back at these comments, posting on Twitter a retort that claimed he would “rather watch paint dry then [sic] watch you play tennis”.
The Australian then suggested that the Norwegian was keen to keep his name in the headlines, and sarcastically wished Ruud luck at the Next Gen ATP Finals, which take place in Milan next weekend.
“Hey @CasperRuud98next time you have something to say, I would appreciate you say it to my face, I’m sure you wouldn’t run your mouth so much after that,” Kyrgios’ tweet said.
“Until then I will continue to rather watch paint dry then watch you play tennis, boring af.
“But again, I also understand why you have to keep my name in your mouth, because people don't even realise that you play tennisgoodluck in Milan champ x.”
Join our new commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies