MELBOURNE, Australia (AP) — Plenty was going badly for Coco Gauff in the second round of the Australian Open.

The double-faults kept coming Wednesday, nine in all. The deficits, too: First, she dropped the opening set against 74th-ranked Sorana Cirstea. Then, after forcing a third, Gauff fell behind by a break, ceding 14 of 16 points with a series of mistakes. Later, after getting even at 3-all, Gauff was a mere two points from a loss.

None of that mattered. As she already keeps showing, over and over, Gauff is not a typical 15-year-old. Not a typical tennis player, either. And by getting past Cirstea 4-6, 6-3, 7-5 in a little more than two hours, she now has set up yet another Grand Slam showdown against Naomi Osaka.

Less than five months after their memorable meeting at the U.S. Open -- Osaka won that one in straight sets, then consoled a crying Gauff on court and encouraged her to address the spectators -- the two will meet again. Like that time, Osaka is the major's reigning champion and Gauff is making her debut at the tournament.

"I know what to expect," said Gauff, who eliminated seven-time Grand Slam champion Venus Williams in the first round Monday. "I'm excited for a good match."

She was not at her very best on a windy day against Cirstea but managed to figure her way out of trouble repeatedly. Gauff demonstrated plenty of grit, yes, and also enthusiasm, pumping herself up by shaking a fist and yelling, “Come on!” after most of her successful points down the stretch.

Late in the third set, Gauff was told by the chair umpire that a serve she hit didn't count because Cirstea had indicated she wasn't ready to receive the ball. Gauff said she never looks at an opponent before serving and asked for a head's up next time.

When the point was played for real, Gauff won it and, from up at the net, stared in Cirstea's direction and yelled. There was plenty more of that sort of celebrating the rest of the way, and Gauff was supported by a Melbourne Arena crowd that chanted, “Let's go, Coco! Let's go!”

Her father, Corey, was animated in the stands, too, except when he was squeezing his eyes shut at critical moments.

There were several of those for his precocious daughter, who was ranked only 313th last year when she became the youngest player in history to qualify for Wimbledon, then wound up beating Williams there en route to the fourth round.

It is a measure of her came-so-soon stardom that Gauff was playing at Melbourne Park's third-largest stadium Wednesday, even though this was a matchup between a pair of players ranked outside the top 60 and with one career Grand Slam quarterfinal between them, more than a decade ago (Cirstea made it that far at the 2009 French Open).

Indeed, every Grand Slam singles match -- "every" being a relative term, of course, because this was No. 9 -- of the 67th-ranked Gauff's nascent career has been placed on a show court.

This was the first main draw match at a major for Gauff in which she held a better ranking than her opponent.

Didn't seem that way at the outset: Gauff dropped the first set. After forcing things to a third, she trailed 3-0. After making it 3-3, Gauff needed to get through one more gut-check: Twice, she was two points from departing.

But the American teenager broke in the next-to-last game, then held to win.

How did Gauff get through this test?

“Just my will to win,” she said. “My parents, they always told me I can come back, no matter what the score is.”

Other winners included defending men's champion Novak Djokovic — he required all of 95 minutes to breeze past Japanese wild-card entry Tatsuma Ito 6-1, 6-4, 6-2 — women's No. 1 Ash Barty and two-time major champion Petra Kvitova, the runner-up to Osaka in Australia a year ago.

Osaka worked through some frustrations Wednesday by grabbing her racket with both hands and chucking it to the ground, tossing away a tennis ball and kicking the racket along the court, to boot.

Then she plopped herself down on her sideline seat and draped a towel over her head. Soon, she was gathering herself and defeating Zheng Saisai 6-2, 6-4.

“I mean, my racket just magically flew out of my hand. I couldn't control it,” Osaka said with a mischievous smile. “I think that's how I dealt with my frustration. It was a bit childish. I just want to play one match without throwing my racket or kicking it. That's all I want.”

Perhaps because her news conference took place while Gauff and Cirstea were still playing, Osaka deflected a question seeking some sort of lookahead to the third round, saying simply she would go watch the end of that match.

In another notable result early on Day 3, former No. 1 and 2018 Australian Open champion Caroline Wozniacki moved on in a tournament she has announced will be the last of her career, erasing big deficits in each set for a 7-5, 7-5 victory against Dayana Yastremska.

The 29-year-old Wozniacki trailed 5-1 in the opening set, then 3-0 in the second, and needed a total of six match points to close things out. Afterward, she teared up as “Sweet Caroline” blared over the loudspeakers in Margaret Court Arena.

___

More AP Tennis: https://apnews.com/apf-Tennis and https://twitter.com/AP_Sports