Taylor Fritz claimed the deciding victory as the United States stormed into an unassailable 3-0 lead over Italy in the United Cup final.

Jessica Pegula and Frances Tiafoe paved the way for Fritz to be the hero with their victories over Martina Trevisan and Lorenzo Musetti earlier in Sunday's final in Sydney.

While Musetti retired hurt while trailing 6-2, WTA world number three Pegula dispatched Trevisan in straight sets, carrying on the form that saw her defeat Iga Swiatek in the USA's semi-final win over Poland.

And Fritz ensured that the inaugural United Cup went his nation's way with a 7-6 (7-4) 7-6 (7-6) win over Matteo Berrettini, who clawed back the first championship point but was unable to prevent his opponent taking the second.

"It's great. It’s amazing for the team to win this event. We came in with really high hopes, or at least I did, for the event," said Fritz, who is ranked ninth in the world by the ATP after winning three titles in 2022.

"I was really happy to be in that position to clinch the match."

There were jubilant scenes as the USA team rushed to celebrate with Fritz, though Tiafoe was perhaps slightly overzealous.

"Just the emotions when you win and everyone comes running at you, it’s amazing," Fritz said. "I don’t know if you saw the replay but Frances basically headbutted me!"

Aryna Sabalenka warmed up for the Australian Open by winning her first WTA title since May 2021 as she beat Linda Noskova in the Adelaide International 1 final on Sunday.

Sabalenka lost in all three of her final appearances in 2022, but she began 2023 in emphatic fashion and crowned a fine week with a 6-3 7-6 (7-4) triumph.

Noskova, who at 18 years and 43 days old became the youngest finalist of a WTA 500-level or above event since 2008, looked up for a scrap as both players threatened to break in the early stages.

But Sabalenka soon took the initiative with the match's first break to go 4-2 up thanks to a ferocious backhand, and she subsequently cruised to seal the set.

The teenager kept things tighter for much longer in the second and went close to tying the match as she found herself 5-4 up and at deuce.

But a tiebreak beckoned, and Noskova's pair of double faults helped Sabalenka open a 5-1 lead, eventually seeing out the win at the second time of asking with a powerful serve that gave her young opponent too much to do.

Sabalenka clinched her success without dropping a single set over the course of the week, something she will hope provides a springboard as she aims to improve on her previous best at the Australian Open, where she reached the fourth round in 2021 and 2022.

Coco Gauff won the third WTA title of her career as she warmed up for the Australian Open by sweeping past Rebeka Masarova in the final of the ASB Classic.

The 18-year-old was too good for Masarova throughout in Auckland, easing to a 6-1 6-1 victory in just an hour and 15 minutes on Sunday.

Gauff forced a break point in Masarova's first service game, and though the Spanish-Swiss player was able to rescue it, she was not so lucky in her next two as her ruthless opponent won the first set with back-to-back breaks.

That theme continued in the second as unforced errors from Masarova, who won just two out of 15 points on her second serve (13.3 per cent), saw Gauff break again immediately.

The American was then forced to save break points on her own serve but did so impressively as she rescued all 10 against her in the contest.

Masarova was able to get on the board again after saving another two break points, but that was as good as it got, with ultimately Gauff romping to victory in front of an impressed New Zealand crowd.

"It's been a great week for me, despite the rain," Gauff said, referring to tournament's frequent weather disruption, which also delayed the final and forced a pause at the end of the first set.

"It's my first title on hard [court] since I was 15, so I'm happy to do well on a surface that I love.

"It gives me a lot of confidence [ahead of the Australian Open]. You're never sure how your first week is going to go, but it's been a great week."

Four-time major champion Naomi Osaka has withdrawn from the 2023 Australian Open.

The 25-year-old Japanese is a two-time Australian Open winner (2019 and 2021), but tournament organisers confirmed on Sunday she will not be adding to that tally in 2023.

No reason has yet been cited for Osaka's decision, although she has not played since pulling out of the Pan Pacific Open in Tokyo in September.

Osaka endured a difficult 2022 at grand slams, losing in the first round at both the French Open and US Open, while she was bundled out in the third round of last year's Australian Open and did not compete at Wimbledon due to an Achilles injury.

The former world number one's withdrawal follows that of men's top seed Carlos Alcaraz and seven-time major winner Venus Williams due to injury. 

Reigning women's singles champion Ash Barty has also since retired following her triumph in January last year.

Osaka is currently ranked 42nd in the world and will be replaced by Dayana Yastremska in the main draw.

Lucia Bronzetti downed Valentini Grammatikopoulou to seal Italy's place in the final of the inaugural United Cup.

Despite losing to Poland in their City Final in Brisbane, Italy claimed a place in the Sydney play-offs as the best-placed runner-up.

Having led 2-0 overnight, Italy were pegged back by Stefanos Tsitsipas' battling 4-6 7-6 (7-2) 6-4 win over Matteo Berrettini.

That put the pressure on Bronzetti's meeting with world number 199 Grammatikopoulou.

Yet despite losing her two previous matches against Grammatikopoulou, world number 54 Bronzetti made no mistake, cruising to a 6-2 6-3 victory.

Italy will now face the United States, who beat Poland 5-0 in their semi-final, in the final on Sunday.

Coco Gauff marched into ASB Classic final with an emphatic defeat of Danka Kovinic, while Linda Noskova upset Ons Jabeur to set up an Adelaide International showdown with Aryna Sabalenka.

Gauff beat Kovinic 6-0 6-2 to move into her first hard-court final since claiming the title in Linz back in October 2019.

The top seed from the United States won the first eight games of a one-sided semi-final, making another statement just over a week before the Australian Open gets under way.

Gauff took only 73 minutes to dispatch seventh seed Kovinic and will face qualifier Rebeka Masarova in the final on Sunday.

Spaniard Masarova reached her first WTA Tour final courtesy of a 6-3 6-3 victory over Ysaline Bonaventure.

The 130-ranked Masarova, a junior French Open singles champion in 2016, served with assurance and struck 16 winners to break new ground.

It was also a memorable Saturday for Czech teenager Noskova, who claimed the scalp of world number two Jabeur with a 6-3 1-6 6-3 victory in Adelaide.

It was the 18-year-old Noskova's second win over a top-10 opponent this week, having also knocked out Daria Kasatkina.

Second seed Sabalenka will be a strong favourite to deny world number 102 Noskova the title on Sunday after she saw off Irina-Camelia Begu 6-3 6-2.

Venus Williams has withdrawn from the Australian Open due to injury and Iga Swiatek's participation could be in doubt.

The American was given a wildcard for the first grand slam of the year, but suffered an injury setback at the ASB Classic this week.

Williams was beaten by Zhu Lin of China in the second round of the tournament in Auckland on Thursday and it was revealed on Saturday she will not play at Melbourne Park.

The 42-year-old, who has shown incredible longevity in her illustrious career, is a seven-time grand slams singles champion and winner of 14 major doubles titles.

Williams won four of her grand slam doubles crowns at the Australian Open and lost her two singles finals in 2003 and 2017.

Australian Kim Birrell has been awarded Williams' wildcard place nine days before the tournament gets under way.

Meanwhile, world number one Swiatek has withdrawn from the Adelaide International 2 next week due to a shoulder injury.

Swiatek was in tears after she was beaten by Jessica Pegula while representing Poland against the United States in the United Cup on Friday.

Iga Swiatek was in tears after losing to Jessica Pegula as the United States took a 2-0 United Cup semi-final lead over Poland, while Italy moved into command against Greece on Friday.

World number one Swiatek was beaten 6-2 6-2 by the impressive Pegula in just 71 minutes at Ken Rosewall Arena.

Swiatek got the better of Pegula three times last year, but the American made light work of seeing off the three-time grand slam champion this time around to put USA in front.

Pegula struck 21 winners, attacking the Swiatek serve in a commanding display just over a week before the Australian Open gets under way.

Swiatek's emotions came out after she was emphatically defeated by the world number three in Sydney.

Pegula said: "I played her today, conditions are totally different than anywhere else I played her. Obviously maybe I had a little bit of an advantage, they just flew in yesterday.

"Definitely the fastest conditions I have played her [in]. Every other place I've played her has been pretty slow. I think that favoured me a lot, and I was able to use that to my advantage and play a really super clean match.

"I think I just was able to execute my game plan probably better than I have previous times."

Frances Tiafoe backed up Pegula's win by beating Kacper Zuk, who replaced the unwell Daniel Michalski, 6-3 6-3.

That ensures Taylor Fritz has a chance to put the United States into the final if he beats Hubert Hurkacz on Saturday.

Italy are in control of the other semi-final following victories for Martina Trevisan and Lorenzo Musetti.

Trevisan upset Maria Sakkari 6-3 6-7 (4-7) 7-5 before Musetti outclassed Stefanos Sakellaridis, winning 6-1 6-1.

Teenage Czech qualifier Linda Noskova upset former world number one Victoria Azarenka to set up a semi-final showdown with Ons Jabeur at the Adelaide International.

In a match lasting almost three hours, Noskova triumphed 6-4 6-7 (3-7) 7-6 (8-6) to continue a dream run in Australia.

Noskova has already beaten third seed Daria Kasatkina in Adelaide and, on only her sixth appearance in a WTA main draw, has won five straight matches.

Further progress will be no easy feat, with top seed Jabeur – a losing finalist at Wimbledon and the US Open in 2022 – grinding out a 7-6 (7-5) 7-5 win over Ukrainian Marta Kostyuk.

On the other side of the draw, second seed Aryna Sabalenka held off a resurgent Marketa Vondrousova to win 6-3 7-5. The Belarusian had led 4-1 in the second set before losing four of the next five games and failing on match point prior to finally seeing it out.

Irina-Camelia Begu defeated fourth seed Veronika Kudermetova 7-5 6-4 to set up a last-four clash with Sabalenka.

At the ASB Classic in Auckland, top seed Coco Gauff outclassed Zhu Lin 6-3 6-2, winning 90 per cent of first-serve points, firing down eight aces, and not giving up a single break point.

Seventh seed Danka Kovinic also won 6-3 6-2 against Viktoria Kuzmova to set up a semi-final clash with Gauff, while world number 95 Ysaline Bonaventure ousted third seed Leylah Fernandez 6-4 6-2 to reach a first Tour-level semi-final where Rebeka Masarova awaits.

Emma Raducanu was in tears as she retired with an ankle injury at the ASB Classic 11 days before the Australian Open starts, while Coco Gauff beat Sofia Kenin to reach the quarter-finals.

Raducanu dished out a bagel to qualifier Viktoria Kuzmova in the first set of the round of 16 match in Auckland on Thursday, but the 2021 US Open champion was unable to continue after losing the second set 7-5.

The 20-year-old Brit ended a disappointing 2022 season early due to a wrist injury and suffered another blow ahead of the first major of this year, leaving the court in tears.

Gauff will be eyeing her maiden grand slam title in 2023 and she impressively dispatched fellow American Kenin 6-4 6-4 in the second round in the capital of New Zealand.

Top seed Gauff and her compatriot were forced to play indoors due to the rain and it was the 18-year-old who prevailed, breaking three times and saving six of the break points she faced.

The teenager will face Zhu Lin of China for a place in the semi-finals after she beat Venus Williams 3-6 6-2 7-5.

Leylah Fernandez inflicted a crushing 6-0 6-1 defeat on Julia Grabher after losing only two games in her first-round win over Brenda Fruhvirtova and the Canadian will now face Ysaline Bonaventure, who defeated Rebecca Marino in three sets.

Top seed Ons Jabeur made a winning start to the season at the Adelaide International, seeing off Sorana Cirstea 7-6 (7-3) 6-1 to set up a meeting with Marta Kostyuk

Irina-Camelia Begu claimed the scalp of Jelena Ostapenko with a 6-3 6-0 upset of the seventh seed, while Victoria Azarenka was a 6-2 7-5 winner against Zheng Qinwen and teenager Linda Noskova got past Claire Liu in straight sets.

Iga Swiatek dragged Poland into the semi-finals of the United Cup with inspired performances in her singles and doubles matches against Italy.

Poland trailed after Lorenzo Musetti and Matteo Berrettini secured wins against Daniel Michalski and Hubert Hurkacz respectively, only for Swiatek and Magda Linette to level things with respective singles victories over Martina Trevisan and Lucia Bronzetti.

That sent the Brisbane city final to a decider in the mixed doubles, which Swiatek and Hurkacz won with ease 6-1 6-2 against Musetti and Camilla Rosatello, though there was a pause in the second set to dry rainfall on the court.

Despite defeat, Italy also advanced to the final four as the city finals loser with the best record.

It was more routine in Sydney as the United States eased to a 4-1 win against Great Britain.

Madison Keys came from a set down to beat Katie Swan, while Jessica Pegula eased past Harriet Dart 6-2 6-0 after Cameron Norrie had defeated Taylor Fritz in three sets.

Despite going a set behind, Frances Tiafoe came back to beat Dan Evans 3-6 7-5 6-3 to clinch the win for his country, before Pegula and Fritz added some gloss after beating Dart and Evans in the mixed doubles.

The third city final in Perth included a thriller as Greece's Stefanos Tsitsipas beat Borna Coric 6-0 6-7 (4-7) 7-5. Donna Vekic had no trouble getting Croatia on the board as she eased past Despina Papamichail 6-2 6-0.

Maria Sakkari put Greece 2-1 ahead when she beat Petra Martic 6-3 6-3, but Borna Gojo defeated Stefanos Sakellaridis in straight sets to make it 2-2.

However, Greece secured the win and their place in the last four after the pairing of Sakkari and Tsitsipas saw off Martic and Gojo 7-6 (8-6) 6-4.

Greece will take on Italy in the semi-finals, while Poland face the USA, with both taking place in Sydney on Friday.

Aryna Sabalenka secured a straight-sets win in her first match of 2023, but was made to work for it by Liudmila Samsonova at the Adelaide International.

The number two seed won 7-6 (10-8) 7-6 (7-3), saving seven set points after going 5-1 down in the first set, before roaring back to take both tie-breaks.

Sabalenka will face Marketa Vondrousova in the quarter-finals, with the Czech having produced a dominant performance in a 6-0 6-4 win against Kaia Kanepi. 

"When it's 1-5 down, it's like you have nothing to lose, and you just go for your shots without thinking," Sabalenka said.

"That really helped me to stay in the set, to keep fighting and to keep trying."

Fourth seed Veronika Kudermetova eased through after a 6-4 6-0 victory against Bianca Andreescu, while Marta Kostyuk also advanced with a hard-fought 6-7 (5-7) 6-2 6-3 win over Elena Rybakina.

At the ASB Classic in Auckland, second seed Sloane Stephens is out after falling to Rebeka Masarova.

Having been forced to resume on Wednesday after rain suspended play the previous day, Stephens struggled against her Spanish opponent, eventually losing 6-3 7-6 (7-5).

Fifth seed Wang Xiyu is also out after retiring from her match against Karolina Muchova, but seventh seed Danka Kovinic is through after a simple 6-1 6-4 win against Nao Hibino.

Kovinic will face Lauren Davis next after she overcame Tamara Zidansek 6-2 6-1, while fellow American Sofia Kenin will take on number one seed Coco Gauff in the last 16 after she beat Wang Xinyu in straight sets.

Boris Becker has swiftly found work after his release from prison, with the German tennis great signed up for television commentary during the Australian Open.

The six-time grand slam singles champion, who took the Australian title in 1991 and 1996, will be part of German Eurosport's team for the season's opening grand slam.

That was announced by the broadcaster on Tuesday, with Becker to co-commentate on big matches and present a 'Matchball Becker' analysis segment twice a day.

Becker, 55, has worked for Eurosport in previous years, as well as being a regular on the BBC's coverage of Wimbledon, a tournament he won three times.

He was released from jail in December, eight months into a two-and-a-half-year sentence handed down as punishment for hiding £2.5million worth of assets and loans to avoid paying debts when he was declared bankrupt in 2017.

Becker, a former coach of Novak Djokovic, reportedly spent the first few weeks of his sentence at Wandsworth Prison in London before being moved to the low-security Huntercombe prison in Oxfordshire in May.

In an interview with Sat.1 after his release, Becker spoke of his experience, saying: "When the cell door closes, the whole world collapses. This is the loneliest moment I've ever had.

"There is only you with your thoughts. There's a carousel in your head, of course. You try to breathe calmly. I was afraid, I didn't cry.

"I believe I rediscovered the human in me, the person I once was. I've learned a hard lesson. A very expensive one. A very painful one."

Emma Raducanu and Coco Gauff both got off to winning starts at the ASB Classic in Auckland on Tuesday.

Raducanu had to come from a set down to beat Linda Fruhvirtova 4-6 6-4 6-2, while top seed Gauff had an easier time of it as she dismissed Tatjana Maria 6-4 6-1 on another day interrupted by the rain.

Second seed Sloane Stephens was only able to get through three games before play was suspended in her match against Rebeka Masarova, while fifth seed Wang Xiyu was 5-3 down in the first set against Karolina Muchova when the rain came.

Fourth seed Bernarda Pera is out after her match with Viktoria Kuzmova resumed having being washed out on Monday, and the American was unable to prevent a 6-4 6-4 defeat, with Kuzmova advancing to face Raducanu in the last 16.

The only two other matches completed on Tuesday saw Elena-Gabriela Ruse beat Erin Routliffe in three sets, and Anna Blinkova overcome Elisabetta Cocciaretto, also in three.

At the Adelaide International, Zheng Qinwen earned a hard-fought victory against number six seed Anett Kontaveit, eventually winning 6-1 4-6 7-6 (9-7).

Eighth seed Ekaterina Alexandrova also crashed out despite winning the first set against Marketa Vondrousova, going on to lose 4-6 6-3 6-2, though seventh seed Jelena Ostapenko is through after beating Karolina Pliskova 6-1 6-3.

In a contest that lasted over two-and-a-half hours despite only two sets being played, Victoria Azarenka beat Anhelina Kalinina 7-6 (11-9) 7-6 (7-5), and will face Zheng next, while Sorana Cirstea will go up against top seed Ons Jabeur in the last 16 after beating Viktorija Golubic in straight sets.

Chris Evert has backed her long-time rival and friend Martina Navratilova to win her latest cancer battle.

American tennis great Evert, who completed her own course of chemotherapy treatment in May after being diagnosed with ovarian cancer, said Navratilova's "strength and resilience" would stand her in good stead.

Navratilova has been diagnosed with throat and breast cancer, she announced on Monday. The Czech-American successfully underwent treatment for breast cancer in 2010 and has said the condition is "serious but still fixable" this time.

Evert's battles with Navratilova in the 1970s and 1980s provided one of the all-time great tennis rivalries.

Both women ended their careers with 18 grand slam singles titles, with Navratilova triumphing a record nine times at Wimbledon. Only Steffi Graf (22) and Serena Williams (23) have won more singles majors among women in the Open Era.

Evert posted on Twitter: "Thinking of @Martina today and supporting her journey, like she did mine, with love and prayers. This is a woman who takes on challenges with strength and resilience…You got this, Martina."

Former US Open champion Tracy Austin sent "prayers and hugs", adding: "Don’t know too many stronger, I know you got this my friend."

Navratilova's long-time former doubles partner Pam Shriver added: "@Martina knows how to put together a winning team. While the news today is difficult, Martina understands how to compete, and take care of herself.

"Her loving family and many friends are ready to support her journey one day at a time. You have this partner!"

Ons Jabeur, who was runner-up at Wimbledon and the US Open last season, said she was "sending my love and my support".