Andy Swales attempts to unravel the fluctuating current fortunes of the leading women ahead of next week's opening Grand Slam of the season ...
It's another wide open affair for the women singles in Melbourne, with more questions than answers regarding many of the game's leading players.
The last eight slams have all been won by different players - not seen since before the Second World War - so trying to pick a winner for the opening major of 2019 is more treacherous than ever.
Simona Halep, who ended 2018 as world No 1, made her comeback from a back injury earlier this week in Sydney and was promptly dispatched by Ashleigh Barty in straight sets.
Defending champion Caroline Wozniacki's best days may already be over, following her disclosure that she has been diagnosed with rheumatoid arthritis.
At present, no player seems capable of winning two or three tournaments in a row so, with the Australian Open starting on Monday, all roads still seem to be pointing towards Serena Williams as a likely favourite.
After all, the 23-time slam winner has reached the final in her last three trips to Melbourne where she is seeking an eighth singles title.
However, the 37-year-old has not competed on Tour since Flushing Meadows in September, so her form and fitness is unknown.
She still yearns to equal Margaret Court's record of 24 slam successes, although time is probably beginning to run out for the game's best player since the start of the new Millennium.
Ashleigh Barty: The 22-year-old from Queensland is hoping to become the first Australian to win the women's singles title in more than 40 years.
Simona Halep: Last year's runner-up who will need to find her rhythm pretty quickly to stand any chance Down Under. Has a tricky first round draw.
Daria Kasatkina: The 21-year-old Russian reached two slam quarter-finals last year and won a reasonably prestigious tournament in Moscow during autumn.
Angelique Kerber: Her experience and coolness under pressure will be her greatest assets over the next two weeks. Winner in 2016, a semi-finalist last year and, of course, is the reigning Wimbledon champion.
Madison Keys: The only player to reach the quarter-finals in four of the last five slams.
Petra Kvitova: Can never be ruled out but hasn't reached a slam semi-final since winning Wimbledon for the second time in 2014. Is a winner of 25 career titles on the WTA Tour. Beat Kerber in straight sets in Sydney this week.
Naomi Osaka: The most recent Grand Slam champion, having triumphed in New York last September. Outdoor hard courts are certainly her speciality.
Karolina Pliskova: The player who should be ready to claim a maiden Grand Slam trophy. Fully equipped to make the breakthrough, and was a winner in Brisbane only last week. Has been a quarter-finalist in Australia for the past three years, while reaching the last eight in six of the most recent nine majors. Was beaten in the US Open final of 2016.
Aryna Sabalenka: The 20-year-old from Belarus is one of the newest stars in women's tennis. Collected her third WTA Tour title in China last week.
Sloane Stephens: One of the most frustrating players of the current generation. She has reached the final in two of the last six slams - winning one - while also losing in the first round in three of these events. A semi-finalist six years ago but hasn't won a match in Melbourne since 2014.
Elina Svitolina: Winner of the end-of-season WTA Finals in Singapore during October, which is her biggest title to date.
Caroline Wozniacki: Returns to Melbourne Park as one of the least fancied defending champions of recent times.