The 29-year-old Dane, who will retire from the sport at the end of the tournament, powered past US world No.92 Kristie Ahn 6-1 6-3 in her first-round encounter.

Wozniacki, unseeded at the Open for the first time since 2008 after slipping to world No.36, was at her consistent best, finishing with only 11 unforced errors to Ahn's 34.

Rain momentarily halted her progression into the last 64 at 4-3 in the second set on Margaret Court Arena.

With the roof closed, Wozniacki held serve easily before breaking the American for a fifth time to close out the match in an hour and 25 minutes.

Wozniacki, who memorably beat Simona Halep in a marathon final in 2018 to break her grand slam hoodoo, said the brief break in play elevated her anxiety as the finish line approached.

"I felt pretty good," she said post-match.

"She was playing really well. She played aggressive with that forehand, mixed the tempo a lot.

"I got a little nervous in the end. I just wanted to close it off. Once the roof came on, it felt like I relaxed a little bit.

"I took some time in between points and was able to finish that one off."

Wozniacki will now meet either 23-seeded Ukrainian Dayana Yastremska or Slovenian qualifier Kaja Juvan next up and is dreaming of an unlikely fairytale finish to her career.

"I hope so," she said when asked if she had another six wins in her.

"I'm going to do my best to go all the way. For now, it's one down and six to go. I'm ready for it."

Elsewhere, women's seeds shone on a gloomy Monday in Melbourne.

Fourteenth-seeded US star Sofia Kenin made short work of Italian Martina Trevisan with a 6-2 6-4 victory.

Croatian Petra Martic, seeded one spot higher than Kenin, handed American Christina McHale a 6-3 6-0 beating.

On court 19, 25th-seeded Ekaterina Alexandrova had a tougher time.

The Russian was pushed to a deciding set by Swiss Jil Teichmann but triumphed 6-4 4-6 6-2 before play on outside courts was suspended as a large downpour settled in over Melbourne Park.

AAP

Australian Associated Press