Aussie Birrell beats wilting Kanepi at AO

If she gets the chance, Kimberly Birrell will reach out to thank the legendary Venus Williams for inadvertently giving her the opportunity to snap a 1462-day grand slam drought.

After a string of serious injuries in recent years, the plucky Queenslander had toyed with the prospect of calling time on her tennis career.

But all the hardship was worth it for glorious days like Tuesday, when Birrell hung tough in searing heat to oust part-time ice trucker and No.31 seed Kaia Kanepi in the opening round of the Australian Open.

The 24-year-old had been preparing to battle it out in the qualifying event at Melbourne Park last week before learning she had been gifted the wildcard originally set aside for Williams.

The former world No.1 opted to hand it back after suffering a leg injury in Auckland.

"I did speak to someone that's friends with (Williams) and I asked if she was in Melbourne because I thought if I saw her in the locker room, I would mention to her that I was the one that ended up getting her spot and say thank you," said Birrell, who is guaranteed to pocket at least $US110,000 ($A158,500) for advancing to the second round at Melbourne Park.

For the record, the 42-year-old Williams' career prize money haul is a cool $US42,406,778 ($A61 million)

"She's such a legend of our sport and I have so much respect for her and Serena and what they've done," added Birrell.

"I also wanted to know if she was OK too, but I think she will be able to continue playing this year and be able to look after whatever injury she had.

"For her to not play here is just kind of just a small thing.

"But for me to get the chance to play in a major slam, especially as the money can be life-changing - I'm pretty grateful."

Estonia's Kanepi - a 37-year-old veteran of seven major quarter-finals - served for Tuesday's match at 5-4 in the second set, but Birrell turned the encounter on its head to win 3-6 7-6 (7-4) 6-1.

The Queenslander's only two previous victories at grand slam level came during her run to the third round back at the 2019 Australian Open.

She was one of just two Australian women to advance to the second round at their home slam this year, joining fellow wildcard Olivia Gadecki, who beat Russian Polina Kudermetova on Monday.

Kanepi drives trucks in her native country in her spare time and for much of the deciding set on Tuesday she looked like she'd rather be back there - or anywhere else really - rather than slugging it out with Birrell under the blazing sun at Kia Arena.

Birrell's second-round opponent will be Czech Linda Fruhvirtova, who beat fellow Australian wildcard Jaimee Fourlis 6-0 6-4 on Tuesday.

Countrywomen Storm Hunter and Talia Gibson were both eliminated on day one.

Australia's highest-ranked female player Ajla Tomljanovic was forced to withdraw with a knee injury two days before the tournament began.