Australian Open champion Serena Williams could not hide her joy after finally surpassing Steffi Graf's Open Era grand slam record by winning a 23rd major singles title.

Serena eclipsed German great Graf after prevailing 6-4 6-4 over older sister Venus in an all-Williams affair at Melbourne Park on Saturday.

While she would not admit it, Serena had longed for the Open Era record, having been stuck on 22 since Wimbledon last year following her semi-final exit at the US Open.

But after almost one and a half hours on Rod Laver Arena, Serena made the record her own as she basked in the glory of a seventh Australian Open crown and a return to the summit of the WTA rankings.

"It's such a great feeling to have 23. It really feels great," Serena told reporters.

"I've been chasing it for a really long time. When it got on my radar, I knew I had an opportunity to get there, and I'm here. I'm here. It's a great feeling. No better place to do it than Melbourne.

"My first grand slam started here, and getting to 23 here, but playing Venus, it's stuff that legends are made of. I couldn't have written a better story.

"I just feel like it was the right moment. Everything kind of happened. It hasn't quite set in yet, but it's really good."

With the Open Era record under her belt, Margaret Court and her all-time feat of 24 is within touching distance.

Asked whether 30 slams were in mind, Serena - seeded second for the tournament - said: "No, no, definitely not. 

"I never had a number. That's the beauty of it. When I started this journey, I just wanted to win a grand slam.

"Every time I step on the court, I want to win. It's just really remarkable."

It was an emotional, family affair as Serena upstaged 36-year-old Venus in Melbourne.

Venus - winner of seven majors - was appearing in the final of a grand slam for the first time since losing to Serena at Wimbledon in 2009.

And while she lost a major decider to Serena for the seventh time in nine meetings, the Williams name was etched on a grand slam singles trophy for the 30th occasion.

"We are just so proud. We feel so fortunate to have this opportunity to be the ones that can do it, you know," Serena added.

"Venus and I work so hard. Still to this day we work side by side each other at practice. We motivate each other. Like I said on the court, every time she won her match, I felt obligated to win, I've got to win, too.

"The motivation she gives me, it's really second to nothing. It's amazing."