Nick Kyrgios of Australia impressively rallied past Stefanos Tsitsipas of Greece at the Association of Tennis Professionals (ATP) grass court tournament Halle Open in Germany on Wednesday to hammer home his status as a Wimbledon threat but only after a spat with the chair umpire over sweating.

Kyrgios defeated world number six and second seed Tsitsipas 5-7, 6-2, 6-4 to reach a second successive quarterfinal after also making the last eight in Stuttgart five days ago.

The 27-year-old smashed his racquet after losing the opener while saving three set points.

He then got into a minor spat with the chair umpire in the third game of the second set, landing himself with a warning for time-wasting.

"He said I was playing too slow – statistically I'm one of the fastest," Kyrgios said.

"I had to walk to the sidelines to get my towel, there is this thing called sweat in 30 Celsius heat that runs down onto your hands. I needed to wipe my hands and he gave me a warning."

Kyrgios immediately sat down mid-game on his bench and thrashed the point out with the chair before returning to the court amid cheers.

"The support I get from crowds around the world is amazing. They want me to go out and put on a show," he said.

Kyrgios called what he judged a frivolous warning "an unnecessary part of the game. It's not needed in a stadium full of people".

"I later hit two aces just to prove my point."

Kyrgios, who has played only five events this season outside of Australia, said he is proud of winning on his own terms – without a coach and playing only when it suits him – while still keeping his ranking at its current 65th.

"There needs to be more grass events for sure, I've been talking about it for ages," he said after defeating the second seeded Greek while saving seven of eight break points in just over two hours.

"If we had six grass court tournaments in Australia, I'd never leave the country."

Kyrgios will play a Friday quarterfinal against Pablo Carreno Busta after the Spanish sixth seed beat American Sebastian Korda 6-4, 0-6, 6-3.

The Australian said that his lack of a massive tennis work ethic is actually a help to his game.

"If I can beat some of the best players in the world and play at this level with as few events as I play, I'm pretty happy.

"I've got a lot of people whom I'm playing for back home and they all want me to keep winning matches like this. This just proves that you can do it all your own way."