Serena Williams is one win away from a record 23rd Grand Slam title after setting up an all-Williams final at the Australian Open against her older sister, Venus.

No. 2-ranked Serena Williams, a six-time Australian Open winner, overwhelmed Mirjana Lucic-Baroni 6-2, 6-1 in the second of the women's semifinals on Thursday after Venus Williams beat fellow American CoCo Vandeweghe 6-7 (3), 6-2, 6-3.

"She's my toughest opponent — nobody has ever beaten me as much as Venus has," Serena Williams said. "No matter what happens, we've won. A Williams is going to win this tournament."

The 36-year-old Venus Williams is back in a Grand Slam final for the first time since Wimbledon in 2009 and her first in Australia since 2003, when she lost the only previous all-Williams final at Melbourne Park.

Venus Williams tossed her racket after clinching the 2-hour, 26-minute semifinal on her fourth match point and put her hands up to her face, almost in disbelief, before crossing her arms over her heart. She then did a stylish pirouette on the court, smiling broadly, as the crowd gave her a standing ovation.

"Everyone has their moment in the sun," Venus Williams said. "Maybe mine has gone on a while. I'd like to keep that going. I've got nothing else to do so let's keep it going."

Serena Williams' celebration was more subdued after her 50-minute, one-sided win over 34-year-old Lucic-Baroni, who was playing her first semifinal at a major since Wimbledon in 1999. Lucic-Baroni took a selfie with her cell phone on the court before waving and leaving Rod Laver Arena.

Serena didn't get to watch much of her sister's match, but she knew the result before she went out to play.

"Obviously I was really proud of Venus — a total inspiration, my big sister," Serena said. "She's basically my world and my life. She means everything to me. I was so happy for her. For us both to be in the final is the biggest dream come true for us."

Venus Williams has won seven major titles, but none since Wimbledon in 2008. Her gap between major finals is the longest for any player in the Open era. She's also lost six of the eight Grand Slam finals she's played against her younger sister, and is 11-16 in career meetings.

Williams and Lucic-Baroni together after their semi-final bout (Getty)

Venus Williams is the oldest player to reach a women's major final since Martina Navratilova, then 37 and 258 days, at Wimbledon in 1994.

The 25-year-old Vandeweghe was playing in the last four at a major for the first time and was the only semifinalist younger than 34. She'd advanced with back-to-back wins over top-ranked Angelique Kerber and French Open champion Garbine Muguruza and took charge against Venus Williams in the first-set tiebreaker.

But Venus Williams rallied after dropping a set for the first time in the tournament, breaking Vandeweghe four times over the final two sets and putting pressure back on her fellow American.

Vandeweghe said earlier in the tournament she'd admired the Williams sisters as an up-and-coming player, and once asked for Venus' autograph. Venus Williams said one of the best things about her longevity in the game was having an influence on other players.

"Growing up, all I wanted was to have an opportunity to play these tournaments. But then you get here and then you have an opportunity to inspire other people," she said. "It's more than a cherry on top. It's more than I dreamed of."

Earlier, Bob and Mike Bryan earned a shot at a seventh Australian Open doubles title after a rain-interrupted 7-6 (7-1) 6-3 semifinal win Friday over Pablo Carreno Busta and Guillermo Garcia-Lopez.