San Francisco Frontiers - Sincaraz, Sabalenka and late nights: Australian Open storylines

AFP Sports picks out five storylines to watch out for.

- Era-defining rivalry -

Without doubt the biggest rivalry in men's tennis today -- so much so that it has its own unofficial name, "Sincaraz".

Spain's Alcaraz overtook the Italian to top the world rankings again at the end of the year. The 22-year-old Alcaraz enjoys a 10-6 lead in their head-to-head record.

However, while Alcaraz has won six major titles, he has never gone beyond the quarter-finals on Melbourne's hard courts.

In contrast, Sinner is the two-time defending Australian Open champion.

Underlining just how little is between the pair, who are good friends off the court, Sinner beat Alcaraz to win the ATP Tour Finals and Wimbledon last year.

Over the same 12 months, Alcaraz defeated his rival to win the US Open and French Open, plus 1000 titles in Rome and Cincinnati.

- Djokovic record at last? -

Novak Djokovic has won the Australian Open a record 10 times and boasts 24 major titles to be tied with Australia's Margaret Court for the most Grand Slam crowns in history.

However, age and injuries are catching up with the 38-year-old Serb and he pulled out of an Adelaide warm-up event this week saying he was "not physically ready".

That, coupled with the outstanding form of Alcaraz and Sinner, means that Djokovic has not won a Slam since 2023 at the US Open.

He reached the semi-finals of all four majors last year but went no further, including retiring with an injury against Alexander Zverev in Melbourne.

Djokovic has refused to set a retirement date and recently said that the Los Angeles Olympics in 2028 -- where he will be defending champion -- was on his radar.

- Venus back at 45 -

Seven-time major singles champion Venus Williams will play at the Australian Open aged 45 after receiving a wildcard.

She will be the oldest woman ever to play at the season-opening Grand Slam.

The American will compete in the main draw at Melbourne Park for the first time since 2021.

Williams, a four-time Australian Open doubles champion, played at the US Open last year and lost in three sets to 11th seed Karolina Muchova in the first round.

The five-time Wimbledon winner and two-time US Open champion has played infrequently in recent seasons.

Her brief appearance at Flushing Meadows was only her fourth singles match of 2025.

- Who can stop Saba? -

Aryna Sabalenka has taken a stranglehold on women's tennis, ending 2025 by finishing world number one for the second straight year.

The 27-year-old Belarusian won a WTA Tour-leading four titles last year, including her fourth Grand Slam crown at the US Open.

So who can stop her? Well, Madison Keys can, the American winning a thrilling three-set final against the defending champion at Melbourne Park 12 months ago.

The hard-hitting Sabalenka was also beaten in the final of the French Open last year by Coco Gauff of the United States.

Moscow-born Kazakh Elena Rybakina defeated Sabalenka in the decider of the WTA Finals and in the quarter-finals at Cincinnati.

Other threats come from world number two and six-time major champion Iga Swiatek and Amanda Anisimova of the United States.

- How late? How hot? -

Grand Slam matches can go on notoriously deep into the night, and nowhere more so than in Melbourne, despite some tepid attempts to improve things.

Andy Murray and home hope Thanasi Kokkinakis slugged it out until 4:05 am in 2023, the Briton barking at one point: "Why are we playing at 3 am?!"

At the 2008 Australian Open Lleyton Hewitt outlasted Marcos Baghdatis in a clash that ended at 4:34 am.

Added to the mix, Melbourne's weather is notoriously fickle and the heat has played havoc with the schedule in the past.

Last week temperatures there topped 40C -- but this week there is a bit of rain forecast and lows of 13C.

I.Rodriguez--SFF