The 23-year-old came through a tense battle between the world's top two players 6-3, 7-6 (7/4), 6-3 on Rod Laver Arena, raising his arms in the air and looking to the sky in celebration.
The victory earned the Italian world number one his third Grand Slam crown.
The former world number one responded on Saturday, posting a photo of an MRI taken of his left hamstring on the social media platform X with the caption: "Thought I'd leave this here for all the sports injury 'experts' out there."
It is Keys's first major title, having reached a second Grand Slam final eight years after her first in New York. She lost on that occasion to Sloane Stephens
Sinner's coach Darren Cahill said it was no surprise for him to see his young charge back in the final, but they were wary of the threat posed by Zverev's overarching desire to finally win a Slam.
The American battled injury and self-doubts last year and curtailed her season early, in October, to get married.
Swiatek said she made far too many mistakes against Keys on Rod Laver Arena and hoped to draw lessons from it.
The 19th seed powered through a thrilling semi-final on a final-set tiebreak against the world number two 5-7, 6-1, 7-6 (10/8) after Sabalenka had earlier swept aside Paula Badosa in straight sets.
The Italian top seed faces Ben Shelton on Friday, just two matches away from a first successful Grand Slam title defence after winning his maiden major crown in Melbourne last year.
Novak Djokovic survived a huge scare to reach the third round of the Australian Open on Wednesday, beating home favourite Alexei Popyrin to stay on track for a historic 25th Grand Slam title.
In her fourth Grand Slam main draw appearance since making her debut at last year's French Open, Andreeva showed maturity beyond her years as Jabeur desperately sought answers from her coaching team after the early jolt.
The second seed, gunning to unseat 10-time champion Novak Djokovic from the world number one spot, was tested in a tight first set but then moved through the gears.
Sumit Nagal, India's top-ranked singles player, was left with less than a thousand dollars in his bank account at one point last year so it was no surprise he was beaming on Tuesday after ensuring a bumper payday at the Australian Open.
A single break proved enough for the French 16th seed to win the opening set against her rusty opponent and she dominated the second set tie-break to progress in Melbourne.
The 36-year-old put up stiff resistance in a 61-minute first set against Argentine Tomas Martin Etcheverry, but the 30th seed slowly ground him down to win 6-4, 6-2, 6-2.
"I'm glad things turned around," Tsitsipas added. "I'm glad I showed the fight and spirit that I usually show on court so it feels great."
An error-strewn Novak Djokovic kickstarted his bid for an 11th Australian Open and unprecedented 25th Grand Slam crown in unconvincing fashion on Sunday, dropping a set to fearless teenage qualifier Dino Prizmic.
World number one Djokovic is gunning for his 11th Australian Open title and 25th major, which would take him clear of Margaret Court on the all-time list.
The changing of the guard in men’s tennis has long been on an asymptotic course, getting closer and closer to the inevitable but not quite materialising.
