Defending Australian Open champion Naomi Osaka squandered two match points as she suffered a shock third-round exit at the hands of unseeded Amanda Anisimova on Friday.

Osaka eased past Camila Osorio and Madison Brengle in straight sets in the first two rounds but fell to a 4-6 6-3 7-6 (10-5) loss to Anisimova in a thrilling contest.

Anisimova, who won her second career title at Melbourne Summer Set 2 earlier this month and is now 8-0 for the season, will face top seed Ash Barty in the last 16.

Two-time Australian Open winner Osaka had won 24 of her past 25 matches in Melbourne and made a fast start against Anisimova by breaking her opponent in the first game.

She held serve to ease ahead on Margaret Court Arena, but Anisimova battled back well in the second set.

The world number 60 broke Osaka in the fourth game with a sublime disguised backhand drop and served out the set in a relatively straightforward manner.

Anisimova continued to dig in and saved two match points in the 10th game to help pave the way for a decisive first-to-10 tie-break.

Osaka had no response to her opponent's accurate hitting as she fell 3-0 behind and, while she did bring it back to 3-2 and 5-4, Anisimova took five of the next six points to advance in a big upset.

DATA SLAM: Osaka outgunned by Anisimova

Osaka had dropped just one set in her first five matches this season and looked in the mood as she raced ahead against Anisimova.

But the American youngster fired in 11 aces and hit more than twice the number of winners that Osaka managed (46 to 21) to pull off the victory.

With this defeat, Osaka has now failed to defend any of her four major crowns, with Victoria Azarenka the last women's player to do so at Melbourne Park in 2012 and 2013.

WINNERS/UNFORCED ERRORS
Anisimova – 46/44
Osaka – 21/45

ACES/DOUBLE FAULTS
Anisimova – 11/8
Osaka – 5/3

BREAK POINTS WON
Anisimova – 1/8
Osaka – 1/10

Defending Australian Open champion Naomi Osaka squandered two match points as she suffered a shock third-round exit at the hands of unseeded Amanda Anisimova on Friday.

Osaka eased past Camila Osorio and Madison Brengle in straight sets in the first two rounds but fell to a 4-6 6-3 7-6 (10-5) loss to Anisimova in a thrilling contest.

Anisimova, who won her second career title at Melbourne Summer Set 2 earlier this month and is now 8-0 for the season, will face top seed Ash Barty in the last 16.

Two-time Australian Open winner Osaka had won 24 of her past 25 matches in Melbourne and made a fast start against Anisimova by breaking her opponent in the first game.

She held serve to ease ahead on Margaret Court Arena, but Anisimova battled back well in the second set.

The world number 60 broke Osaka in the fourth game with a sublime disguised backhand drop and served out the set in a relatively straightforward manner.

Anisimova continued to dig in and saved two match points in the 10th game to help pave the way for a decisive first-to-10 tie-break.

Osaka had no response to her opponent's accurate hitting as she fell 3-0 behind and, while she did bring it back to 3-2 and 5-4, Anisimova took five of the next six points to advance in a big upset.

Ash Barty defeated Elena Rybakina in straight sets to claim the Adelaide International title, while Simona Halep clinched silverware in Melbourne.

World number one and heavy favourite Barty prevailed 6-3 6-2 against Rybakina to claim the Adelaide title for a second time in three seasons.

The 25-year-old recovered from 40-15 down in the seventh game and went on to immediately earn the only break of the opening set.

Barty did not look back as she held throughout the second set, meaning she went 35 consecutive games without losing serve to conclude the tournament.

After securing a 14th WTA singles title in a little over an hour, Barty now turns focus to next week's Sydney Tennis Classic ahead of beginning her Australian Open campaign.

"I feel good leading up to an Australian Open like I have every year," Barty, who hit 17 winners to 13 unforced errors, said after seeing off Rybakina. 

"Each and every preparation is unique. We take it for what comes and what it is, move on, try and do the best that we can in every opportunity.

"It has absolutely no effect on the way that I prepare or the way I'm thinking leading forward just because it's a Grand Slam. It doesn't change for us."

Halep, one of Barty's likely rivals for the Australian Open crown, also made a bright start to the year by overcoming Veronika Kudermetova in the Melbourne Summer Set 1 final.

The number two seed, who is aiming to put last year's injury-ravaged and trophyless season behind her, came out on top 6-2 6-3.

She recovered from an early break down in the first set and again in the second to make it 23 career titles, and a first since the 2020 Italian Open.

It could easily have been a different story, however, as Kudermetova had three break points to move 3-0 ahead in the second set, but the Russian could not take full advantage.

Amanda Anisimova defeated Aliaksandra Sasnovich at the Melbourne Summer Set 2 final to claim the first WTA title of the season, and her second overall.

Belarusian qualifier Sasnovich hit back in style to take the second set 6-1 after losing the opener 7-5, but Anisimova recovered from a break down to edge the deciding set 6-4.

In doing so, Anisimova became the first American to win a title on Australian soil since Sofia Kenin's Australian Open triumph in 2020.

Belinda Bencic got her grass-court season under way with a battling victory over qualifier Jule Niemeier in the first round of the inaugural bett1 Open.

Fifth seed Bencic came from a set down to beat 167th-ranked German Niemeier 4-6 6-4 7-5 in Berlin on Monday.

The 21-year-old Niemeier was playing her first professional match on grass and gave a great account of herself against the world number 12, who needed two hours and 12 minutes to secure her place in the second round.

Bencic secured the only breaks in the second and third set to ensure she will face Petra Martic or Asia Muhammad in round two.

Madison Keys progressed in straight sets, getting the better of Polish qualifier Magdalena Frech 6-3 6-4.

The American, a winner of two WTA singles titles on grass, struck 19 winners as she set up an encounter with top seed Aryna Sabalenka.

There were also first-round victories for Alize Cornet and Ekaterina Alexandrova earlier in the day over Amanda Anisimova and Anna Kalinskaya respectively.

Coco Gauff continued her fine form with a 6-3 6-3 quarter-final triumph over fellow American Amanda Anisimova at the Emilia-Romagna Open.

In a contest between two teenage stars, it was 17-year-old Gauff who sealed her second semi-final spot in as many weeks, having made the last four at the Internazionali d'Italia.

Third seed Gauff will face Katerina Siniakova next, after the Czech followed up her win over Serena Williams with a 7-5 6-1 defeat of Caroline Garcia.

"I was pretty satisfied with the way I played," Gauff said, after fending off Anisimova.

"I do think I could have served a little bit better, but other than that, I was pretty happy with the way I played."

Despite her valid concerns, Gauff won 72 per cent of points after landing her first serve and forced six breaks to win in style, reeling off six games on the trot from 3-0 behind in the second set.

The other semi-final will see second seed Wang Qiang take on Sloane Stephens.

Wang prevailed 7-6 (7-4) 3-6 7-5 against Petra Martic, while Stephens saw off Sara Errani 6-3 6-0.

It was another rain-affected day at the Serbia Open, where Maria Camila Osorio Serrano managed to get past Kamilla Rakhimova 4-6 6-3 6-4.

Anna Kalinskaya and Reka Luca Jani were locked at one set apiece in the only other match to get started before the weather halted play.

Amanda Anisimova raced into the second round at the Emilia-Romagna Open, where she could now face wildcard Venus Williams.

Venus and Serena Williams have each entered the event in Parma to prepare for the French Open, although Bianca Andreescu has been forced to withdraw.

Both Williams sisters have qualifiers in their openers at the start of next week, but Venus – absent in Rome with a knee injury – already knows tricky teenager Anisimova lies in wait beyond that.

Anisimova was a force in the 2019 clay-court season, then just 17 but winning the Copa Colsanitas – still her sole WTA Tour title – before beating Simona Halep at Roland Garros to reach the French Open semi-finals.

A return to the red dirt in 2020 yielded only three wins, though, two of them at the major before Halep gained revenge, and this season has been similarly testing.

But fifth seed Anisimova eased through her opener on Sunday, beating home hopeful Jasmine Paolini 6-2 6-1 in just shy of an hour.

Daria Kasatkina, the number four seed, could also face a grand slam winner in round two, with Sloane Stephens – the 2017 US Open champion – potentially her prize after seeing off Hsieh Su-wei in straight sets.

Qiang Wang had to come through three sets but ensured there were no upsets on day one as she defeated Misaki Doi 6-2 5-7 6-1.

Petra Kvitova recovered from a poor start to beat Magda Linette in the first round of the Internazionali BNL d'Italia on Monday.

Linette took just 31 minutes to win the first set in Rome, but world number 10 Kvitova responded superbly to win 1-6 6-0 6-2.

Two-time grand slam champion Kvitova racked up 16 unforced errors in the first set, yet rallied like the great competitor she has proved to be for so long to ensure she will face Vera Zvonareva - conqueror of Christina McHale - in the second round.

The 11th seed from the Czech Republic said: "The first set I started very badly. I was missing almost everything. On the court... [the ball] was bouncing everywhere as well. A little bit windy. I just had to get used to probably everything.

"The beginning of the second set when finally I held my serve and broke her serve, I think since then it was much, much better."

French Open champion Iga Swiatek advanced when Alison Riske retired at 5-4 down in the first set due to a recurrence of a left foot injury.

Swiatek, who will take on Sloane Stephens or Madison Keys in the second round, made 18 unforced errors but had won four games in a row from 4-1 down when the American was unable to continue. 

Coco Gauff battled past Yulia Putintseva 7-5 4-6 6-4 to set up a meeting with 17th seed Maria Sakkari  - who fended off qualifier Polona Hercog 7-6 (8-6) 3-6 6-2.

Amanda Anisimova will do battle with Elina Svitolina, a winner of this tournament twice, after defeating Wang Qiang 7-5 6-3. Jessie Pegula, Jennifer Brady and Petra Martic were among the other winners on day one.