When Naomi Osaka won her fourth major title at the 2021 Australian Open, it felt like she would lead the women's game for years to come as both an athlete and an advocate.

Later that year the Japanese superstar opened up about suffering depression, taking extended breaks from the tour as a result, before an even longer absence as she gave birth to her daughter Shai in 2023.

Now the 26-year-old is back from maternity leave and says returning as a mother has given her a "different mindset".

The early signs are she remains the same talent, showing glimpses of her explosive shot-making and fleetness of foot on her return in Brisbane last week.

There is no doubt Osaka has the technical tools to go back to the very top. How quickly she can challenge for the biggest prizes again remains to be seen.

Poland's Iga Swiatek has dominated the WTA game for almost two years and a fine start to 2024 has seen the world number one extend her unbeaten run to 16 matches after helping Poland reach the United Cup final.

Sabalenka is continuing to push Swiatek. The 25-year-old Belarusian, who briefly replaced Swiatek at the top of the rankings last season, reached at least the semi-finals of all four majors in 2023 and will be confident of a strong title defence in Melbourne.

Sabalenka saw her 15-match winning streak ruthlessly ended in the Brisbane final by Kazakhstan's 2022 Wimbledon champion Elena Rybakina, who is another serious contender.

And it will be fascinating to see how American teenage Coco Gauff, who defended her WTA title in Auckland last week, will deal with her new-found status as a Grand Slam champion after a triumphant US Open victory which illustrated her growing maturity and inner belief.