Serena Williams beat sister Venus in straight sets to win her seventh Australian Open and an Open-era record 23rd Grand Slam singles title.
The American regains the number one ranking from German Angelique Kerber.
Australia’s Margaret Court, with 24, is the only player still ahead of Serena in terms of Grand Slam singles titles.
“Congratulations Serena on number 23,” said Venus, who at 36 was the oldest Australian Open finalist in the Open era.
“I have been right there with you, some of them I lost right there against you. It’s been an awesome win.
Serena paid tribute to her sister, who was playing her first major final for eight years, saying: “There’s no way I would be at 23 without her. There’s no way I’d be at one without her. She’s my inspiration.
“She’s the only reason I’m standing here today. She’s the only reason the Williams sisters exist. Thank you for inspiring me. Every time you won this week, I felt like I got a win too.”
Serena Williams secured an Open-era record 23rd grand slam title by beating her older sister Venus to become Australian Open champion.
Watch Sereva vs Venus Williams Australian Open finals Highlight
After a nervous start, Serena proved unstoppable again on Rod Laver Arena as the American won 6-4 6-4 to claim her seventh Melbourne crown.
Venus arrived on the crest of a wave, having reached her first major final since 2009, but in truth she was second-best throughout here and an upset never looked likely.
These contests have always been more respectful than raucous and it was the same again as Serena quickly apologised to her sister when an early throw-up went awry.
Best behaviour momentarily went out the window when the younger sibling lost balance and instantly cracked her frame in frustration. Umpire Alison Hughes called out a warning for racket abuse.
Suddenly, however, the favourite was jolted into life as a driving backhand winner gave her the break for 5-3, before serving out the set with an ace.
The moment came at 3-3 when Venus saved two break points but finally succumbed to a third, Serena’s stinging forehand proving too strong as her opponent responded wide.
Just as in the first set, Venus held to make her sister serve out and there was a sniff of a comeback when she led 15-30.
Two forehands into the net, however, conceded championship point and when a last Venus backhand dropped wide, her younger sibling fell on her back in celebration.
The crowd on Rod Laver Arena had been backing Venus from the beginning as she tried to win a first major title for eight years, and all the more so as defeat loomed and she appeared to struggle physically.
There was a huge cheer when she held serve to force her sister to serve out the match, but Serena recovered from 15-30 to earn match point and fell back on the court in celebration as her sister sent the ball floating wide.
Court was sitting in the crowd here and it is not inconceivable Serena could pass the Australian’s tally at Wimbledon this summer and, numerically at least, assume position as the greatest female player of all-time.
As well as pocketing the champion’s cheque of 3,700,000 Australian dollars (£2.2 million), she will also reclaim the number one ranking, moving above Germany’s Angelique Kerber when the list refreshes on Monday.
She has more than justified that billing in Melbourne, where she lifts the Daphne Akhurst Memorial Cup having not dropped a single set in seven matches.
At 35, Serena also becomes the oldest female grand slam champion in the Open era, extending the record she set by winning Wimbledon, aged 34, last year.
When victory was confirmed after a brisk 82 minutes, the game’s most successful siblings met for a warm embrace at the net.
This was Serena’s 17th victory in 28 matches against Venus, 19 years after they first met professionally at this tournament in the second round.