Novak Djokovic continues to confound as he builds an incredible tennis legacy.

At age 36, he produced one of the most dominant seasons of his tennis career in 2023, completing it with victory at the ATP Finals in Turin.

With his first round-robin victory over Holger Rune, Djokovic ensured he would end the year at world No.1 for a record-extending eighth time. This week he will spend his 400th week at the top of the rankings.

Djokovic’s complete domination of Carlos Alcaraz and Jannik Sinner in the semifinals and finals respectively secured a record seventh ATP Finals crown.

“It’s one of the best seasons I’ve had in my life, no doubt," Djokovic said.

“I’m very proud of the performances these past two days against Alcaraz and Sinner, probably the best two players in the world next to me and Medvedev at the moment — and the way they have been playing, I had to step it up.

“Overall it was a phenomenal week.”

It will be hard to find someone in better form at next month’s United Cup, where Djokovic will lead Team Serbia into battle in Group E in Perth.

But one of those players could be Iga Swiatek, the women’s world No.1 who is also bound for RAC Arena.

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Swiatek was arguably even more dominant at the WTA’s season-ending tournament. She did not drop a set in winning all five singles matches – the last a thumping 6-1 6-0 win over Jessica Pegula in the final.

Her WTA Finals triumph meant she, too, ended the season as world No.1. She will carry an 11-match winning streak into her opening match for Team Poland on Saturday 30 December.

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"Coming back to world No.1, it's a dream come true, for sure," said Swiatek, after displacing Aryna Sabalenka from the top spot.

"I would say I wasn't expecting that right now, this season. I was hoping that maybe next year is gonna be my year, but it seems like, you know, just working hard and focusing on the right things at the end worked, so I'm really happy."

Swiatek will partner Hubert Hurkacz for the second straight year at the United Cup. Given the combined strength of their top-10 singles rankings, Poland is the No.1 seed in 2024, headlining Group A.

Incredibly, Perth will see a third No.1 in action, in Storm Hunter.

She forms part of a strong Australian team at the United Cup, led by Aussie singles No.1 Alex de Minaur, plus three-time major quarterfinalist Ajla Tomljanovic and fellow doubles stars Matt Ebden and Ellen Perez.

Team Australia has landed in the exciting Group C alongside fellow Grand Slam countries USA and Great Britain.

Hunter was in Cancun with Swiatek at the WTA Finals, where in the women’s doubles event with Elise Mertens, she went 3-0 in the group stages to qualify for the semifinals.

That result, plus the fact Pegula and Coco Gauff did not reach the semifinals, was enough to ensure Hunter would become year-end doubles world No.1.

She is the first Australian to achieve this milestone since Samantha Stosur in 2006.

“To be honest, it still hasn’t really sunken in. It’s crazy,” Hunter said the following week.

“I honestly didn’t think this would ever happen to me in my life. It was kind of a dream that just always was there, but kind of seemed impossible.

“It’s definitely been a whirlwind few days.”

Tickets to the United Cup group stages in Perth, which begin 29 December, are on sale now through Ticketek.