Serena Williams will have to beat her sister Venus to win an Open era record 23rd grand slam title after she overcame Mirjana Lucic-Baroni at the Australian Open.

Williams brought an end to Lucic-Baroni's fairytale run in Melbourne with an emphatic 6-2 6-1 victory, which ensures the most prestigious siblings in tennis will meet for a ninth major final and their first since Wimbledon in 2009.

A win for Serena would see her finally pull clear of Steffi Graf's Open-era record 22 grand slam titles and move just one short of Margaret Court's all-time best 24.

Venus had earlier beaten fellow American Coco Vandeweghe 6-7 (3/7) 6-2 6-3 on Rod Laver Arena to advance to her first major final in eight years.

Their reunion adds another chapter to a throwback Australian Open, in which Serena and Venus, aged 35 and 36 respectively, will go head to head for the women's title while Roger Federer, 35, and Rafael Nadal, 30, may yet do battle for the men's.

Serena will be favourite. She has won seven of her last eight meetings against her older sister and holds a 16-11 advantage overall, since the pair first met professionally in the second round here 19 years ago.

Lucic-Baroni, who turns 35 herself in March, was given a rapturous reception as the Croatian recorded on her phone the final seconds of her brilliant tournament.

The world number 79, who has resurrected her career after a lengthy period of personal trauma, was into her second grand slam semi-final, 18 years after her last at Wimbledon in 1999.

"She's an inspiration and really deserves all the credit," Williams said.

"I'm honoured to play her, she played so hard to get this far and after everything she's gone through, she inspires me."

On her title match with Venus, she added: "She's my toughest opponent, no-one has ever beaten me as much as Venus has. She has a pretty good record against me.

"No matter what happens we've won, she's been through a lot, I've been through a lot. To see her do so well it's great so I look forward to it. A Williams is going to win this tournament."

Venus was the oldest entrant in the singles draw and now the oldest to make a major final since 37-year-old Martina Navratilova reached the last hurdle at Wimbledon in 1994.

"I didn't watch her match before but I was really proud," Serena said.

"She's a total inspiration, my big sister, she's basically my world and my life.

"She means everything to me and I was so happy for her obviously. I couldn't be happier for her results and for us both to be in the final is the biggest dream come true for us."

Williams broke twice in the opening set and managed to win every point on her first serve as Lucic-Baroni, with her legs heavily strapped, was unable to live with the pace and precision of her opponent.

She held serve in the first game of the second set but that was her last as Williams raced through six in a row.

When a final forehand missed its mark, the American held her arms up to the sky, celebrating victory after a brisk 50 minutes.