Defending champion Naomi Osaka and eighth seed Serena Williams were sensationally knocked out of the Australian Open third round on Friday.

Unseeded 15-year-old Coco Gauff shocked third seed Osaka in straight sets while the 38-year-old by China’s Wang Qiang on Friday, torpedoing her bid for a record-equalling 24th Grand Slam crown.

The American prodigy, making her Melbourne debut this year, followed her win against Venus Williams in the first round by stunning the Japanese player 6-3, 6-4 in their second meeting. Williams, 38, was the favourite to win an eighth title at Melbourne Park but she came unstuck against a determined Wang, losing 6-4, 6-7 (2/7), 7-5.

Gauff, the youngest player in the draw will play 14th seed Sofia Kenin of the United States or China’s Zhang Shuai.

“Oh my gosh. Two years ago I lost the first round in the juniors and now I’m here – this is crazy,” said Gauff. “I was just telling myself one point at a time and just keep fighting because you never know what happens on this court.”

This was the second instalment of a budding rivalry that could light up tennis for the next decade or more, having met at the US Open, where Osaka won easily.

Wang, the 27th seeded Chinese player had won only one game off the American the last time they met in the US Open quarter-finals, but she took the early advantage by winning the first set. She was broken while serving for the match as the 38-year-old American forced a decider.

But serving second in the third set, Williams leaked errors and Wang converted her third match point on her opponent’s serve to cause the biggest upset of the tournament so far.

Her reward is a clash with Tunisia’s Ons Jabeur, who upset Williams’s close friend Caroline Wozniacki and sent the Dane into retirement.

Wozniacki’s glittering tennis career ended when she went down in three, in what could be called another upset.

The Danish former world No 1, who announced in December that this would be her final tournament, lost 7-5, 3-6, 7-5 in the third round.

The unseeded 29-year-old brings the curtain down on a career that saw her win 30 WTA titles, with her sole Grand Slam triumph coming in 2018 at Melbourne Park.

Alison Riske also made her way to the fourth round on Friday with a three-set victory against Julia Goerges. The 18th seed was blown away in the first set but fought back hard to win 1-6, 7-6(4), 6-2. She will now face home favourite Ashleigh Barty in the next round.

Earlier in the day, world No 1 Barty said she played her best match this year in blowing away 29th seed Elena Rybakina 6-3, 6-2 to barrel into the fourth round.

Barty needed just 78 minutes to dispose of the young Kazakh as she bids to become the first Australian to win the women’s title since 1978.


3rd round

Ashleigh Barty (AUS x1) bt Elena Rybakina (KAZ x29) 6-3, 6-2

Petra Kvitova (CZE x7) bt Ekaterina Alexandrova (RUS x25) 6-1, 6-2

Ons Jabeur (TUN) bt Caroline Wozniacki (DEN) 7-5, 3-6, 7-5

Alison Riske (USA x18) bt Julia Goerges (GER) 1-6, 7-6(4), 6-2