American 17-year-old Amanda Anisimova stunned 11th seed Aryna Sabalenka in straight sets to reach the last 16 at the Australian Open.

The youngest competitor left in the draw won 6-3 6-2 to become the first player born in the 2000s to reach the fourth round of a Grand Slam.

“This is an unreal feeling, I can’t believe that this is happening right now,” said the tournament debutant.

The world number 87 faces two-time Wimbledon champion Petra Kvitova next.

The Czech eighth seed, who won last week’s Sydney International, beat Belinda Bencic of Switzerland 6-1 6-4 in 68 minutes.

“I’m feeling pretty good on the court physically and my mindset’s good. I’m serving well too, which is important,” said Kvitova.

Meanwhile, American Danielle Collins, who overcame 14th seed Julia Goerges in the opening round, moved into round four with a 6-3 6-2 win over France’s 19th seed Caroline Garcia.

Next up for Collins will be 2016 champion and second seed Angelique Kerber, who thrashed Australian wildcard Kimberly Birrell 6-1 6-0 in 58 minutes.

Former world number one Kerber, on her 31st birthday, was far too good for the 20-year-old, who had caused a shock in the second round when she defeated 29th seed Donna Vekic of Croatia.

• Sharapova beats champion Wozniacki
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Anisimova ‘can’t believe’ she won

Anisimova’s only other two Grand Slam appearances at the French and US Opens ended in first-round exits.

The youngster used her power to unleash 21 blistering winners and an accurate first serve on Belarusian Sabalenka, who had been among those fancied to challenge for the title in Melbourne.

“I was expecting a really tough match, she’s a great player, so I really can’t believe I got through this round,” Anisimova said.

“I’m feeling really good out here, I played some great tennis.”

She becomes the youngest American to reach a Grand Slam fourth round since Serena Williams at the French Open in 1998, and the youngest in Melbourne since Jennifer Capriati in 1993.

Stephens comes through stiff test

Fifth seed Sloane Stephens was made to work hard in her third-round victory over Croatian 31st seed Petra Martic.

The American 2017 US Open champion carved out just one break point – which she converted after having been broken herself in the first set – in a 7-6 (8-6) 7-6 (7-5) win.

She will face world number 44 Anastasia Pavlyuchenkova in the last 16 after the Russian’s 6-0 6-3 victory over world number 31 Aliaksandra Sasnovich of Belarus.

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Defending champion Caroline Wozniacki was knocked out of the Australian Open as five-time Grand Slam winner Maria Sharapova provided a reminder of her ability with a three-set win.

Russia’s Sharapova, seeded 30th, hit 37 winners in a 6-4 4-6 6-3 victory to reach the fourth round.

Wozniacki, 28, led 4-1 in the first set, only to see Sharapova battle back.

The third seed broke in the final game of the second to level, Sharapova edging a tight third in Melbourne.

The 2008 Australian Open champion took her second match point to win in two hours and 24 minutes and set up a fourth-round meeting with Australia’s Ashleigh Barty on Sunday.

“I thought the level was quite high. I knew I’d get a tough match,” Sharapova, 31, said.

Danish world number three Wozniacki, defending the ranking points won in Melbourne last year, is set to slide down the standings as a result of the defeat.

• Federer sweeps aside Fritz to advance
• Teenager Anisimova upstages Sabalenka
• Live scores, schedule and results

Sharapova’s talent shines through

Sharapova has been unable to climb back into the upper echelons of the game since returning from a doping ban in April 2017, making just one Grand Slam quarter-final at last year’s French Open.

But against Wozniacki she proved she still has the talent – and, most importantly, desire – to cause problems for the world’s best.

It was not Sharapova’s biggest win in terms of ranking since returning, having also beat Simona Halep – who was then second in the world – at the 2017 US Open.

While she obviously impressed with her quality of play, her sheer will-to-win also stood out.

Against one of the game’s fittest and most relentless players, the Russian won 17 of 23 rallies which lasted nine shots or more.

That included a pivotal moment at 4-4 in the first set where she switched hands in a 23-shot rally to stay in the opening point and went on to win it.

In turn, she went on to hold and broke in the next game on her way to the opening set.

Sharapova was constantly screaming in celebration after seeing winners go in and an intense fist-pump at her box moments after clinching victory illustrated how much it meant.

“I haven’t played many matches in the last year against top players so it was really rewarding to win that last set,” she said.

“These are the kinds of matches I train for.”

Wozniacki unable to scale Slam heights again

Defeat is another blow for Wozniacki, who announced in October she has been diagnosed with rheumatoid arthritis.

The former world number one came into the first Grand Slam of the year with little hype, perhaps because she has not gone past the last 16 at a major since winning in Melbourne and lost to Canadian teenager Bianca Andreescu in Auckland earlier this month.

She found encouragement by easing past Belgium’s Alison van Uytvanck and Sweden’s Johanna Larsson – both ranked outside the top 50 – in the opening two rounds here.

But, against Sharapova, she was outfought.

Wozniacki was among one of the most vocal critics of Sharapova following her doping ban, leading to Sharapova’s agent Max Eisenbud dismissing the Dane as a “journeyman”.

Yet there was a civilised handshake at the net as Wozniacki congratulated Sharapova on her performance.

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British brothers Neal and Ken Skupski lost 6-3 6-4 to Finland’s Henri Kontinen and Australia’s John Peers in the second round of the men’s doubles at the Australian Open.

The pair have never gone beyond round two in Melbourne.

They comfortably beat Australians James Duckworth and Jordan Thompson 6-3 6-4 in the first round.

Briton Dom Inglot is in men’s doubles action later on Friday and Harriet Dart plays in the women’s doubles.

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Britain’s Johanna Konta was knocked out of the Australian Open in a second-round match against Garbine Muguruza which finished at 03:12 local time.

Konta, 27, lost 6-4 6-7 (3-7) 7-5 in Melbourne in one of the latest finishes in the tournament’s history.

Spaniard Muguruza, 25, nicked a tight final set in front of about 250 remaining fans on Margaret Court Arena.

“I don’t agree with athletes having to physically exert themselves in the early hours,” Konta told BBC Sport.

“I don’t think it is healthy – in fact I think it is quite dangerous.

“In the circumstances I thought we put on a great match and it’s a shame more people couldn’t see it.”

Konta’s defeat means there are no British players left in the singles in Melbourne.

She said they were not given the option to postpone the match until day five.

The latest finish in Australian Open history is a 2008 third-round match between Lleyton Hewitt and Marcos Baghdatis that ended at 04:34.

Two-time Grand Slam champion Muguruza took her first match point to win in two hours and 42 minutes and reach the third round.

“I can’t believe there are people watching us at 3:15am,” the former world number one said.

“We play for you guys watching – otherwise why are we here?

“It was very tough. Johanna played very good, serving incredibly and hitting big shots. I just tried to hang in there.”

Konta pipped in match which neither deserved to lose

The players did not walk out on to Melbourne Park’s second show court until 00:22 local time after the final match of the day was pushed back as a result of Kei Nishikori’s win over Ivo Karlovic and Alexander Zverev’s victory against Jeremy Chardy both taking almost four hours.

When the match between Zverev and Chardy went into a fifth set, tournament organisers were planning to switch the match to court three – but halted that plan with fourth seed Zverev rattling towards victory.

British number one Konta threw the first ball at 00:30 local time in what was an eerie atmosphere in front of a sparse crowd in the 10,000-seat arena.

Despite the enforced wait, both women produced a high-quality match in which they provided reminders of their pedigrees after falling down the rankings in recent times.

The match could have swung either way, with defeat harsh on whoever ended up the loser.

Konta hit a forehand into the net after Muguruza upped the ante to clinch victory with only the second break of the match.

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Britain’s final singles hope bows out

Konta was Britain’s last remaining singles hope at the first Grand Slam of the year, having seen seven of the nation’s players – including Andy Murray and men’s number one Kyle Edmund – lose in the opening three days.

Konta, now ranked 38th in the world, reached the Melbourne semi-finals in 2016 but a pronounced dip in form saw her drop as low as 50th in the world last summer.

Despite the nature of the defeat, she will take encouragement from one of her best performances in recent times.

Konta made a slow start, losing her serve in the opening game and unable to win a point on Muguruza’s first two service games.

But she grew into the contest and matched Muguruza’s power in an entertaining battle.

Konta hit 13 winners in the first set as she attacked, but was unable to convert a break point for 3-4 when she missed a cross-court forehand – one of 13 unforced errors which ultimately proved the difference.

Both missed break points in a tight second set – Konta in the fourth game and Muguruza in the ninth – leading to a tie-beak.

Konta earned a mini-break with a wonderful deep backhand, moved to the brink with an ace down the middle for 6-3, then took the match into a decider with a forehand winner.

Serve continued to dominate in the final set, with Konta winning 31% of receiving points and Muguruza’s 29%, and not a single break point on offer.

A final-set tie-break looked destined to settle the match until Muguruza seized control.