Serena Williams has tennis history at her mercy as she looks to rewrite the record books yet again in Saturday night's heavyweight Australian Open final.

The oldest women's finalist of the open era and already the owner of a record five singles titles at Melbourne Park, Williams, 33, can take another mighty leap towards sporting immortality with victory over Maria Sharapova.

In the first title match in more than a decade featuring the world's top two players, Williams can surpass legends Martina Navratilova and Chris Evert as America's most successful grand slam champion with a 19th career major.

And that would edge Williams to within three titles of Steffi Graf's open-era benchmark 22 majors and to just five shy of Australian Margaret Smith Court on the all-time grand slam leaderboard.

Only illness or an inspired performance from Sharapova can seemingly stop Williams, who has battled a head cold all campaign and was again seen suffering during a practise session cut short on Friday.

Despite the stakes, Williams said she was playing with the house's money in her first Open final since 2010.

"I've won this tournament several times. I don't have to go out there and have another title," she said.

"I want it, but it's not life or death for me. I think that helps me relax. So, yeah, she absolutely has nothing to lose and I have nothing to lose, so it will be fun."

Sharapova feels on song after extending her 2015 unbeaten run to 10 matches in Melbourne, but admits her unflattering 2-from-18 head-to-head record against the world No 1 is a concern.

Sharapova's only wins over Williams came in 2004 at Wimbledon and the season-ending championships.

The second seed will need to snap an 11-year, 15-match losing streak to stop her career-long nemesis from staking her latest claim as the women's greatest-ever player.

"It's tough knowing that she has such a powerful game and I've had trouble against her," the Russian said.

"On the other side, when it's a final situation and knowing I'm a big competitor, I'll do everything I can to try and win the match.

"When you're playing a grand slam final, you have to focus on what's ahead and not the results, and that's what I'll be looking to do."

With Williams firing down a tournament-best 70 aces, and a total of 41 per cent unreturnable deliveries in her first six matches, Sharapova knows she must take her chances.

"If she's serving aces, and serving extremely hard, and finding her spot, then sometimes that's a tough day," she said.

"But if you find yourself in the rally, then you've got to be smart.

"She's someone who makes you go for a little bit more than you would like."

While Williams is gunning for a 19th grand slam crown, Sharapova, the reigning French Open champion, is playing for a sixth - and first at Melbourne Park in seven years after losing finals in 2012 to Victoria Azarenka and 2007 to Williams.

"I feel like it's been a really long time since I've won this title here, and it would be extremely meaningful for me to hold the trophy," Sharapova said.

"I've had a very difficult tournament coming back from two match points down in the second round.

"I feel like I got a second life, another opportunity and I'm trying to make the most out of it." - AAP