MELBOURNE, Australia — Madison Keys of the United States upset two-time defending champion Aryna Sabalenka of Belarus 6-3, 2-6, 7-5 in the Australian Open final on Saturday night to collect her first Grand Slam title at age 29.

By adding this win over the No. 1-ranked Sabalenka to an elimination of No. 2 Iga Swiatek in the semifinals on Thursday — saving a match point along the way — Keys is the first woman since Serena Williams in 2005 to defeat both of the WTA’s top two players at Melbourne Park.

Keys, ranked 14th and seeded 19th, was playing in her second major final after being the runner-up at the 2017 US Open.

She prevented Sabalenka from earning what would have been her third women’s trophy in a row at the Australian Open — something last accomplished by Martina Hingis from 1997-99 — and her fourth major title overall.

When it ended, Keys covered her face with her hands, then raised her arms. Soon, she was hugging her husband, Bjorn Fratangelo — who has been her coach since 2023 — and other members of her team, before sitting on her sideline bench and laughing.

Sabalenka chucked her racket afterward, then covered her head with a white towel.

The men’s final is Sunday, with defending champion Jannik Sinner against Alexander Zverev. Sinner is seeded No. 1, Zverev No. 2.

Sinner eliminated American Ben Shelton in the semifinals, while Zverev advanced when 24-time Grand Slam champion Novak Djokovic stopped playing because of an injury.

Keys is the oldest woman to become a first-time major champion since Flavia Pennetta was 33 at the 2015 US Open. This was the 46th Slam appearance for Keys, which ranks as the third-most major tournaments before winning a trophy in the Open era, behind only Pennetta’s 49 and Marion Bartoli’s 47 when she won Wimbledon in 2013.

It was the more accomplished Sabalenka who was shakier at the outset. Keys broke three times in the first set, helped in part by Sabalenka’s four double-faults and 13 total unforced errors.

Don’t for a moment think this was merely an instance of Sabalenka being her own undoing.

Keys certainly had a lot to do with the way things were going, too. She compiled an 11-4 edge in winners in that first set, managing to out-hit the big-hitting Sabalenka repeatedly from the baseline.

For a stretch, it seemed as though every shot off the strings of Keys’ racket — the one she switched to ahead of this season to protect her oft-injured right shoulder and to make it easier to control her considerable power — was landing precisely where she wanted.

Near a corner. On a line. Out of Sabalenka’s reach.

Also important was the way Keys, whose left thigh was taped for the match, covered every part of the court, racing to get to balls and send them back over the net with intent. On one terrific defensive sequence, she sprinted for a forehand that drew a forehand into the net from Sabalenka, capping a break for a 4-1 lead.

Never one to hide her emotions during a match, Sabalenka frequently displayed frustration while trailing on the scoreboard, kicking a ball after netting a volley, dropping her racket after missing an overhead, slapping her leg after an errant forehand.

Sabalenka took a trip to the locker room before the second set, and whether that helped clear her head or slowed Keys’ momentum — or both — the final’s complexion soon changed. Keys’ first-serve percentage dipped from 86% in the first set to 59% in the second. Sabalenka raised her winner total to 13 in the second set and began accumulating, and converting, break points.

When she sent a backhand down the line to force an error by Keys for a break and a 2-1 lead in the second, Sabalenka shook her left fist and gritted her teeth as she walked to the sideline.

When she broke again to go up 4-1, Sabalenka marked the occasion with a long and loud scream while looking in the direction of her team.

By the time the last set arrived, the action was tight and tense, without so much as a single break point until its final game, when Keys came through with one last forehand winner.