MELBOURNE:Rafael Nadal insisted "I really don't care" after Nick Kyrgios turned up the heat on their simmering rivalry by mimicking the Spaniard's signature serving routine.

Kyrgios theatrically copied Nadal's laborious pre-serve ticks during his Australian Open second round clash against Gilles Simon, pretending to tuck his hair behind his ears and picking at his underwear.

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Even the umpire had to chuckle at Kyrgios, who had been penalised for taking too long to serve. Kyrgios's opponent did his own Nadal impression when he was also warned for slow serving, sending the Australian into giggles.

But Nadal, who has history with Kyrgios, brushed off the impersonation.

"I am here to play tennis. Honestly, I don't care at all. If was funny, good. That's it," said the Spaniard.

Kyrgios has a testy relationship with Nadal. Last year he described the world number one as "super salty" after the 19-time Grand Slam winner accused him of lacking respect.

"There wasn't any extracurricular activities I was doing before my serve to waste time," said the Australian, who has previously criticised Nadal for the time he takes between points.

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"I mean, it happened. That's the ref's discretion whether I went over the clock or not," he added.

His French opponent Gilles Simon also mimicked Nadal when he was given a time violation.

Asked who's impersonation was better, Kyrgios said: "I don't know. I don't wear underwear, so... probably Gilles."