Players from 12 nations are set to compete in the men's hard court tournament in Melbourne after completing their mandatory 14-day quarantine period upon arrival in Australia.

Since the start of the coronavirus pandemic, most tennis events have been held behind closed doors.

But fans will be allowed to watch the action at the ATP Cup with the crowd capacity capped at 25 per cent.

Djokovic was among several big names to take part in an exhibition event in front of a full house in Adelaide and the 33-year-old said he was looking forward to using the fans as a spur in Serbia’s title defence.

"I’ve missed seeing crowds in the stands the most," said the 17-time major winner.

"At this stage of my career, after playing professional tennis for more than 15 years, that is one of the biggest driving forces or motivations, inspirations.

"Playing in front of a crowd, feeding off that energy and exchanging great passion and joy that I, and the fans, have for the sport.

"This country has done a great job dealing with this virus.

"I'm grateful that we have an opportunity to practise, to play and to compete in the sport that we love.

"We are all excited to be here."

Djokovic is among 14 of the world’s top 15 players that are set to play in the ATP Cup with each team consisting of four players.

Serbia have been pitted against Canada and Germany in Group A, while last year’s runners-up Spain face Greece and Australia in Group B.

Austria, Italy and France make up Group C, while Group D consists of Russia, Argentina and Japan.

Australia entered the competition as hosts with the other 11 countries qualifying based on their ATP ranking of its highest-ranked singles player.

The winners of each group qualify for the semi-finals.

The ATP Cup is one of five warm-up tournaments ahead of the Australian Open which is scheduled to run from February 8 to 21.

World number two Rafael Nadal is hoping to put on a show as he bids to help Spain go one better than last year after they lost 2-1 to Serbia in the final.

"[We will] try to give to the fans around the world and the fans here in Australia a good show," said Nadal.

"For some of the people who are suffering a lot at home, we will try to [provide] good entertainment for them.

"I just [want to] congratulate the country for an amazing effort to contain the virus here.

"It’s one of the best examples in the world about how to do the things well in this particular case.

"We appreciate so much the effort that the country and Tennis Australia have done to allow us to be here and play our sport."

The number of countries competing has been cut from 24 to 12 compared to last year’s inaugural ATP Cup due to the coronavirus pandemic.