The 23-year-old top seed is viewed as the best opportunity in years to end the home drought, but dropped the first set to Ukraine's Lesia Tsurenko at Melbourne Park today.

Sets two and three were much more comfortable as she eventually came through 5-7, 6-1, 6-1 to book her place in round two.

No Australian player, male or female, has won the event since Chris O'Neil captured the women's title in 1978.

"I felt comfortable knowing that I just needed to change a few things, to adjust, to try and bring the match back in my favour," said Barty, who won her first Grand Slam at the French Open last year.

"I think the crowd was incredible. 

"Certainly, once I got a bit of a roll on, they became more and more influential, I think. 

"It was pretty nice to play in front of a full crowd tonight."

Most of the action on day one was confined to the show courts, which have roofs, as heavy rain cancelled all play outside.

It means tomorrow is set to be a bumper day of matches to make up for what was lost.

Japan's defending champion Naomi Osaka was among others to go through as the third seed breezed past Czech player Marie Bouzková 6-2, 6-4.

American legend Serena Williams began her quest for an eighth Australian Open by seeing off Russia's Anastasia Potapova 6-0, 6-3.

The eighth seed needs just one more Grand Slam to draw level with Australian Margaret Court's all-time record for men and women on 24.

Serena's sister Venus did not enjoy her day as she was beaten by 15-year-old sensation Coco Gauff in an all-American duel.

The teenager also beat Venus Williams at Wimbledon last year and recorded a 7-6, 6-3 win against the seven-time Grand Slam champion.

Denmark's 2018 Australian Open champion Caroline Wozniacki made it through by defeating American Kristie Ahn 6-1, 6-3.

Two-time former Wimbledon champion Petra Kvitová of the Czech Republic, seeded seventh, ousted compatriot Kateřina Siniaková 6-1, 6-0.

The biggest seed to fall was American Sloane Stephens, ranked 24th, as the former US Open winner lost 2-6, 7-5, 6-2 to China's Zhang Shuai.

In the men's draw, Serbia's defending champion Novak Djokovic dropped a set before beating Germany's Jan-Lennard Struff 7-6, 6-2, 2-6, 6-1.

The second seed has 16 Grand Slam titles to his name, including a record seven at the Australian Open.

"It's great to be back in this arena that has a very special place in my heart," said Djokovic. 

"This has been by far the most successful court in my career, I love coming back to Australia, the land of tennis."

Swiss icon Roger Federer, the third seed, eased past American Steve Johnson 6-3, 6-2, 6-2.

He is hoping for a 21st Grand Slam crown and a seventh in Australia.

Greece's World Tour Finals champion Stefanos Tsitsipas, seeded sixth, knocked out Italy's Salvatore Caruso 6-0, 6-2, 6-3.

Canada's 13th seed Denis Shapovalov was the highest-ranked player to exit after he lost 6-3, 6-7, 6-1, 7-6 to Hungary's Márton Fucsovics.