Post-match, Kyrgios gave his side of the story as to what caused the brouhaha.
Kyrgios also tried the underarm serve during his win over Nadal, with the Spaniard accusing him of lacking respect for his opponents and the crowd, although Kyrgios subsequently earned the support of Roger Federer, who said it was a fair tactic when the receiver was standing deep behind the baseline.
The exchange continued throughout the sixth game of the first set, Kyrgios later adding: "You got nothing else to do on a Sunday night?" So you obviously don't have anything else to do'.
"And then he was like, 'You're a dick, ' and said it again". And then he was like, "come here and say it".
Just give me the answer.
"He said I had a s--ty haircut. I haven't been to a barber shop in a couple of days, so he was pretty right", Kyrgios said.
Tony Jones took aim at Kyrgios on the Today show on Monday, saying the tennis bad boy needed to be sidelined by the ATP Tour.
And he soon revealed what the fan apparently said to Kyrgios during the mid-match altercation.
"It was a lot of fun". It's one of my favorite tournaments.
"You've just got idiots in the crowd who have nothing else to do on a Sunday night but watch me play, yet are talking to me as though they're not interested in watching", he told reporters.
Kyrgios laughed as he traded barbs with the spectator, who stood and appeared to gesture for the Australian to come closer, while the unfortunate woman sitting next to him looked like she wished she was elsewhere.
"If anything, he got me going, motivated me a little bit more". "I served well and returned well and I'm really happy".
Nick Kyrgios cruised into the final 16 in Miami, but his match against Dušan Lajović wasn't without fireworks.
The fiery young Aussie won two points in the opening set, including set point, with an underarm serve, which left Lajovic stunned and had the crowd jeering.
But the fan was soon escorted away from his seat to the delight of Kyrgios and everyone else in the arena.
"I think tennis needs stuff like this, to be honest", he said.