Novak Djokovic called Australia his "happy place" on Saturday as he prepared to kick off his season at the United Cup with a tricky clash against China's fast-improving Zhang Zhizhen.

The world number one holds no grudges heading into the mixed team event nearly two years after being refused entry to the country over his stance on Covid-19 vaccinations.

"Always felt like... (Australia) was my happy place where I felt great, other than that situation two years ago where obviously it wasn't really enjoyable," he said.

"But other than that, I have always enjoyed myself, played the best tennis, and so my feelings coming into Australia this year are really positive."

The 36-year-old said he is looking forward to facing the 58th-ranked Zhang in Sunday's group tie in Perth.

Djokovic is targeting a record 11th Australian Open title next month, but his focus for now is on Zhang, vowing to give "always 100 percent".

China laid down a marker on Saturday with a defeat of the Czech Republic, which featured Wimbledon champion Marketa Vondrousova.

"I never faced Zhang," he said. "I think he now is probably the most successful Chinese male player of all time.

"That's great, as well, because we want to see the men's tennis in China picking up. They are a strong team, very strong team."

But the 24-time Grand Slam winner warned: "Hopefully I can start the new season with a win."

The Serbs, trained by former player and Djokovic friend Viktor Troicki, have been in the city for several days trying to acclimatise.

"Australia is not really around the corner for us Europeans, so we need a little bit of time to get used to the time difference," said Djokovic.

"Obviously different conditions here than any other place where I trained or played an exhibition recently.

"China had a clean sweep today," he added. "There's a big Chinese community here and also Serbian community, so hopefully we can feel the energy in the stands and support for both nations."