Serena Williams was eight weeks pregnant during her 2017 Australian Open triumph, and while she has failed to add to her tally of 23 Grand Slam titles, the American is still regarded as the dominant force in women's tennis on her return to Melbourne.
The 37-year-old took a year off after the birth of her daughter, Alexis Olympia, in September of that year, before returning to action last season, when she reached the finals at Wimbledon and the US Open.
Her quest for another major fell at the final hurdle on both occasions, however, with defeats by Germany's Angelique Kerber in London and rising Japanese star Naomi Osaka in New York.
The defeats left Williams still seeking a 24th Grand Slam singles title to equal Margaret Court's all-time record and she will have another tilt at that milestone during the January 14-27 event, despite entering the tournament ranked 16th in the world.
While Williams achieved her victory over sister Venus in the final two years ago, the challenge this year is expected to come from a vast array of players.
Chris Evert has described trying to pick a women's singles champion in Melbourne as a "crapshoot", with the last eight Grand Slam titles having been won by different players.
World No1 Simona Halep has had a fractured lead-up to the tournament, with a back injury cutting short her 2018 season in September.
She will be without a coach for the first few months of the season after Darren Cahill left for "family reasons" and if that setback was not enough, she was outplayed by unseeded Australian Ashleigh Barty in the second round of the Sydney International.
The Romanian, who lost the 2018 Australian Open final to Caroline Wozniacki, could rue her lack of competitive matches but remained upbeat, while saying she had low expectations for the year's first Grand Slam.
"I think I played a good level of tennis ... No pain at all. I'm happy about that. It's a great sign," Halep told reporters after her defeat by Barty.
A second Australian Open title for Kerber, who denied Williams in the 2016 final, will be a perfect birthday gift for the world No 2, who turns 31 during the first week of the tournament.
She looked sharp at the Hopman Cup, maintaining a 100% singles record, even though Germany lost to Roger Federer's Switzerland in the final.
Defending champion Wozniacki has been battling rheumatoid arthritis but the 28-year-old Dane will remain a contender, as will 21-year-old Osaka, who jumped into the spotlight with her ruthless victory over a fired-up Williams in New York.
Belarussian Aryna Sabalenka has emerged as a dark horse, with many observers, including American great Evert tipping the 20-year-old to make her Grand Slam breakthrough in 2019.
Sabalenka surged up the WTA rankings last year with her first two titles and arrived in Melbourne fresh from winning another tournament in Shenzhen.
"I have no reason to believe that Sabalenka will not win more than one Grand Slam. Why? I see two things. I see hunger and I see boldness," 18-times major singles champion Evert said in a conference call looking ahead to the Australian Open.
"The boldness, fearlessness, confidence. That's her swagger, I see that. Like, this girl wants it. You can see it in her eyes. She's pretty intense."
Meanwhile, Rafael Nadal revealed yesterday that he was back to full fitness and has a brand new serve to unleash at the Australian Open.
The world No 2 limped away from Melbourne Park a year ago, forced to retire in pain from his quarterfinal with Marin Cilic. The 17-time Grand Slam champion missed most of the next three months and cut short his season to have surgery on a troublesome foot injury.
He pulled out of a Brisbane warm-up event with a slight thigh strain but declared yesterday his troubles were behind him.
"I feel good. If I am not feeling good, I will not be here," Nadal told reporters two days before the start of the first Grand Slam of the year. "I have good feelings in terms of the surgery.
"After surgery, after months without competing, having trouble practising, of course there are always issues when you come back.
"But it's nothing new for me," added Nadal, who admits he has to manage the workload on his creaking 32-year-old body, battered by years of his all-action style. To better cope, he has remodelled his serve to help extend his career.
"There are always things to improve," said the Spaniard, who faces Australian wildcard James Duckworth in the first round. "The serve was always a thing that I tried to improve, and I think I did.
"I am happy with the motivation to do something new. If I am able to make that happen in a good way, that hopefully it will give me the chance to help me on my game longer term. I didn't compete with this new serve, so let's see how it works. I am confident it's going to work well."
His 2018 season ended with another injury retirement in the US Open semifinal but Nadal still managed to win five tournaments in a truncated season, including a record-extending 11th French Open to leave him just three Grand Slams behind Roger Federer's all-time record of 20 majors.
Nadal said he was sad to hear that Andy Murray was to quit tennis this year because of chronic hip pain. Nadal said he could relate to it having had his own injury issues over the years, but he had always been focused on getting back on court.
"My only goal is always to have been to keep going," he said. "That's the only way that you can keep having confidence and hope for a good comeback in terms of health.
"But I know that tennis is not forever. I want to do it as long as I can and give myself the best possibilities to fight for the things really I am passionate about. When the day arrives I cannot do it will be the day to go and do another thing."..