Daniil Medvedev, who was world No.1 just five months ago, has rued the ban on Russian players at the new inter-country United Cup tournament playing across Australia this week.

Medvedev, who was preparing to turn out in the ATP 250 Adelaide International on Sunday, said the chance to team up with high-quality teammates – Russia won the Davis Cup in December 2021 – was a missed opportunity.

“I would definitely prefer to play United Cup. We would be the only team with four players in the top 10. [We’d be] good favourites,” a chatty Medvedev said.

“I completely understand why we are not playing the team competitions, where we would represent our own country.

“I play where I can play. I am really happy to play Adelaide. It’s exciting. Everybody is a little bit nervous before the first tournament of the year and it’s really special.”

Meanwhile, doubts surround Nick Kyrgios, who dropped out of the United Cup last week with an ankle injury.

He is scheduled to play another ATP 250 tournament, also in Adelaide, next week.

Kyrgios’s Australian Open 2022 doubles partner Thanasi Kokkinakis was unable to say on Sunday whether his headline-making mate would show up in South Australia.

Adelaide tournament director Alistair MacDonald was also non-committal about Kyrgios’ playing plans.

“Obviously we would love to have Nick play here in week two and we understand he is preparing for the Australian Open. We would love to be a part of that,” he said.

The United Cup, a $15 million prize money event contested across Brisbane, Perth and Sydney is, however, looking a curious concept already.

Played over 10 days, the 18-country tournament has had an uneven start.

It had an underwhelming public reaction in Queensland and, while Sydney has enjoyed good crowds, the Australia team that lost 3-2 to Great Britain in its opening match did not boast the most compelling line-up – with Maddison Inglis falling to Harriet Dart and Zoe Hives defeated by Katie Swan.

Australia’s Davis Cup squad went under the radar even when reaching the final in Spain just five weeks ago and, with its pumped-up exhibition vibe, the new team offering already feels a tournament too far.

Somehow the more intriguing names are in Adelaide this week and next.

None come bigger than nine-time Australian Open champion Novak Djokovic, who made it safely though South Australian immigration.

The memory of the five days in a Melbourne deportation centre will stick with him forever, the Serb said, but even in practice, he will take some beating anywhere this southern summer (on Saturday, the crowd watching Australia’s James Duckworth fled the court mid-match when it was announced that Djokovic was practising nearby).

The calibre of player in Adelaide this week and next (the city hosts two ATP and two WTA tournaments in the first two weeks of January) is extraordinary.

“I have not seen a 250 [event] this strong. Holger Rune is 11 in the world and he is seeded five here. That’s insane,” said Kokkinakis who will play both Adelaide tournaments.

“This is strong for a 500 event. It could be a Masters.”

Kokkinakis faces American Maxime Cressy first up in a half of the draw that includes young guns Rune, Felix Auger-Aliassime and Jannik Sinner.

Rune, just 19 and guided by Serena Williams’ coach Patrick Mouratoglou, has the momentum and confidence. Ranked 103 this time last year, he said his goal was to be No.1.

Three years older, Auger-Aliassime is another with realistic ambitions to win a major tournament. Watch out Melbourne in two weeks.

The WTA 500 also in Adelaide this week is high in quality too, with wildcards Jaimee Fourlis and Priscilla Hon as the sole Aussie entrants.

There are top-flight clashes everywhere: 2017 Wimbledon champion Garbine Muguruza losing to recent US Open champion Bianca Andreescu in Sunday’s opening match stood out but in the pre-tournament media interviews, the world No.2 Tunisia’s Ons Jabeur, shone.

Twenty eight years old and runner-up at Wimbledon and the US Open last year, Jabeur came through the ranks with Ash Barty.

The Aussie’s retirement revelation should not have been such a shock, she said.

“I was not really surprised because I know Ash and once she achieves everything she tries to win, she wants to move into something else. I have a lot of respect for her. We played juniors together. It’s also sad to see her leaving,” she said.

“If she stayed she could win all the grand slams. But the most important thing is she was happy with what she was doing and she had enough of tennis and now she wants to move into something else.

“This year is all about Ons Jabeur. She is going to win the Australian Open,” she said. “Similar game just different nationalities.”

As well as wit, Jabeur is not without insight.

A spectator at last month’s FIFA World Cup final in Qatar, she was happy to talk about the image of the host country that consumed the western media.

“I think it was unjust, to be honest with you. There is in every country you can find something [that] is not right,” she said.

“Qatar is organising the World Cup and everybody was criticising and if you go to any country you respect their culture and for me it was, you go there [then] you respect them.

“It was the cleanest World Cup ever. There was no stealing. There was no crime. Nothing happened. People were very respectful there. It’s time to maybe let these countries shine and I think Qatar had a great organisation.”