World number one Ashleigh Barty on Monday pulled out of this week's Sydney Classic after opening her season by winning the singles and doubles titles at the Adelaide International.

The 25-year-old's name was scratched from a revised draw with local reports saying she needed to recover from her Adelaide exploits, with the Australian Open starting in one week.

Barty demolished Kazakhstan's Elena Rybakina 6-3, 6-2 to claim the 14th singles title of her career on Sunday then returned to win the doubles with Storm Sanders.

It was Barty's first tournament in four months, since a shock third-round loss at the US Open in September, after which she opted to remain in Australia because of the pandemic.

But the reigning Wimbledon champion bounced back to show why she is favourite to win her maiden Australian Open crown.

Barty beat a host of top players in a stacked top half of the Adelaide draw, including Coco Gauff (world number 19), Sofia Kenin (12) and Iga Swiatek (8) on her way to the decider.

Her first-round bye in Sydney has been handed to third seed and world number four Barbora Krejcikova, with world number three Garbine Muguruza now the top seed.

Former French Open champion Swiatek, who fell to Barty in the Adelaide semis, also withdrew from Sydney.

"After a tense pre-season and last week's tournament in Adelaide I feel like my body needs more time to recover before @australianopen," the Pole said on Twitter.

"I've been feeling some pain in my lower rib area, which is why unfortunately I've decided to withdraw from the tournament in Sydney. See you in Melbourne!"

Swiatek was due to open her Sydney campaign against US Open champion Emma Raducanu, who missed the Melbourne Summer Set tournament last week as she continued to recover from coronavirus.

The Briton will instead play Rybakina.

In early Sydney action, Spain's world number nine Paula Badosa swept past Latvia's Jelena Ostapenko 7-6 (7/1), 6-1 and fifth-ranked Estonian Anett Kontaveit beat China's Zhang Shuai 6-3, 6-3.