Her ambition is to one day be regarded as "the greatest" and few who witnessed how she took the tennis world by storm at Wimbledon last year would question her potential to perhaps be mentioned in that conversation in decades to come.

Key points: Cori "Coco" Gauff is the youngest player in the main draw at the Australian Open

Cori "Coco" Gauff is the youngest player in the main draw at the Australian Open Gauff will face defending champion Naomi Osaka in the third round on Friday

Gauff will face defending champion Naomi Osaka in the third round on Friday The 15-year-old made headlines when she beat Venus Williams in the Wimbledon first round last year

For now, though, teenage phenomenon Cori "Coco" Gauff is intent on making a resounding statement at the Australian Open and so far she has delivered on her mission.

The athletic 15-year-old, who is the youngest player in the women's draw in her Open debut, earned passage through to the third round at Melbourne Park on Wednesday to set up a blockbuster match-up with defending champion Naomi Osaka.

It will not be the first time the two have met; few will forget the heart-warming aftermath that followed their encounter at the US Open last September when Osaka consoled an emotional Gauff after beating her younger rival in straight sets.

Friday's clash promises to be every bit as memorable and Gauff cannot wait to show Osaka what she has learned since her third-round defeat in New York four months ago.

"I think I'll be less nervous this time," said Gauff, who is ranked 67 in the world.

"I think [at the] US Open I was nervous. It was my first time on [Arthur] Ashe [Stadium]. We're both familiar with each other's games.

"She plays really aggressive. This time coming in, I'm going to be more aggressive."

Gauff is playing in only her third major and her first Australian Open. ( AP: Dita Alangkara )

The aggression Gauff wants to show against Osaka was on full display in her first-round win over Venus Williams, who she beat at Wimbledon to became the youngest player in 28 years to win a main-draw match after coming through qualifying.

Her gripping victory over Sorana Cirstea on Melbourne Arena on Wednesday also showed her ability to scrap, as she trailed 0-3 in the third and final set before clawing her way back to win 4-6, 6-3, 7-5.

"I think I was just trying to stay calm, mostly, and stay positive," Gauff said.

"I've always believed that I can come back regardless of the score."

The crowds watching her victories over Williams and Cirstea definitely appreciated her refusal to give up and she has quickly become a Melbourne Park favourite in her first appearance at the Open.

Gauff announced herself on the world stage when she beat Venus Williams at Wimbledon. ( AP: Tim Ireland )

She experienced a similar level of support on her run to the fourth round at last year's Wimbledon before her tournament came to an end at the hands of the eventual winner, Simona Halep.

Gauff's maiden appearance at a major proved to be no flash in the pan, as she not only made an impression at the US Open but also won her first WTA title in Linz on hardcourt in October when she had to qualify for the tournament.

From a ranking of 313 before Wimbledon, Gauff finished 2019 at number 68 and she will enjoy another rise even if she does not advance beyond the third round in Melbourne.

'I don't want to lose'

Facing the big names does not intimidate Gauff — who turns 16 in March — and her comments in the wake of beating Williams on Monday suggest that the reputation of her opponent on the other side of the net means nothing to her.

"I believe I can beat anyone," said Gauff, who stands at 175 centimetres tall.

"If it happens, I don't know. But I think that's almost every player's mentality. The ones [players] who are the great ones, they don't really fear anyone.

"You respect your opponent, but you can't go into the match fearing someone, because then you're going to lose and I don't want to lose."

The on-court exploits of Gauff, who was born in Atlanta but moved to Florida as a child, are not the only reason tennis fans around the world find her captivating.

Her relationship with her father Corey, a former US college basketball player, has attracted significant interest, especially since an entertaining video of the two at the recent WTA event in Auckland went viral on social media.

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While Corey Gauff helps with the coaching of his daughter, working alongside the Mouratoglou Tennis Academy team, his role extends beyond making sure her serve is right and her ground strokes are solid.

Before matches they say a prayer together and often his final instruction is simply to "have fun".

Her father even helps out with her driving lessons now that she has gained her learners' permit in the US.

"My dad lets me drive more than my mum," a smiling Gauff revealed at her media conference following her win over Cirstea.

"But my mum, I try to force her to let me drive."