MELBOURNE: Madison Keys was true to her word.

Haunted for eight years by her 2017 US Open final flop, the American underdog unleashed a devastating performance of power and poise to stun world No.1 and two-time defending champion Aryna Sabalenka.

Madison Keys, grand slam champion.

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Those words seemed inevitable when Keys burst onto the professional scene as a precocious 14-year-old.

But she could never quite put it all together until now, as, backed by ice cool husband/coach Bjorn Fratangelo, she outgunned Sabalenka 6-3, 2-6, 7-5 on Rod Laver Arena.

Tears of joy flowed for the popular and unpretentious 29-year-old, who had promised to not die wondering a second time around after resembling a deer in the headlights in her previous major final.

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“This is where I’m gonna cry,” Keys said in a heartwarming and hilarious speech after finally getting her mitts on the Daphne Akhurst Memorial Cup.

“I have wanted this for so long, and I have been in one other grand slam final and it did not go my way. I didn’t know if I was ever going to get back to this position to try to win a trophy again. And my team believed in me every step of the way. So thank you so much.

“They believed in me when I didn’t believe in myself, and helped me every step of the way. Last year was so tough, with some really bad injuries, I didn’t know if I was gonna be able to do it again. And to be here and have this trophy, and my husband, who is looking dazed and confused over there… I love you all so much.

“Now I am dazed and confused. I want to say thank you so much, so appreciative to every single person who helped me continue to believe in myself, push on to achieve this dream. Thank you so much.”

Pre-match, Keys spoke of being “consumed” by nerves against Sloane Stephens in that previous 6-3, 6-0 nightmare in New York.

On a blustery Saturday night in Melbourne, those nerves turned into a fearless display of tennis as Keys won her 12th straight match Down Under, having already claimed the Adelaide International.

“A detonation of power,” Sam Smith described it as on Nine.

As the 19th seed, Keys becomes the lowest ranked player to win the Australian Open women’s singles title since Serena Williams in 2007.

Williams, coming back from injury, was ranked the world No.81 when she became the first unseeded player to win the title since Christine O’Neil in 1978.

Keys also becomes the first women’s player since Williams in 2005 to beat the world’s top two players en route to the title at Melbourne Park.

A red hot Keys knocked out No.2 Iga Swiatek in the semi-finals.

She becomes the oldest first time winner of a women’s grand slam title since a 33-year-old Flavia Pennetta lifted the 2015 US Open.