So long to the first Grand Slam of the year. Naomi Osaka was once again crowned the Australian Open champion with a straight-sets win against Jennifer Brady. But so much more went down, leaving us with these takeaways:  

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1. Naomi Osaka is the tour's dominant force

Between last year's shutdown and Osaka's decision to withdraw from last autumn's clay swing, Osaka competed in just four tournaments in 2020.

But the numbers are undeniable. Osaka's Australian Open title extended her winning streak to 21, the longest since Serena Williams's run of 27 in 2014-15. In the past decade, only one player not named Serena has compiled a longer streak. Victoria Azarenka raced out of the blocks in 2012 with 26 straight wins. Osaka has not lost a match in more than a year, since a 6-3, 6-0 setback to Sara Sorribes Tormo in Billie Jean King Cup action on clay last February. Since the 2019 US Open, Osaka has won 37 out of 40 matches.

Read more: Pam Shriver's final word

Osaka's stranglehold on her competition is becoming clearer, so too is her ascension into the echelon of all-time greats. She is the 16th player in the Open Era to win four or more majors. She has exceeded the tallies of Lindsay Davenport, Jennifer Capriati and Angelique Kerber and equaled those of Kim Clijsters, Arantxa Sánchez Vicario and Hana Mandlikova. Osaka is now just one major title behind matching Martina Hingis and Maria Sharapova.

So how will Osaka react to pulling away from the pack? Her performance in the first major final in which she was the significant favorite could be an indication. She admitted to being "extremely nervous" during it, but made peace with that. Accepting her nerves meant that she was "probably not going to play well," Osaka managed to focus on simply competing. 

On Naomi Osaka's Roland Garros debut in 2016, she defeated Jelena Ostapenko and took Simona Halep to three sets.

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2. The challenge of natural surfaces

Osaka's dominance is legit, but comes with a caveat. She has won four of the past six hardcourt majors, yet has failed to make the second week at either Roland Garros or Wimbledon. She has not reached a WTA Tour final on those surfaces nor has she defeated a Top 20 player on clay or grass.

Ahead of the Australian Open final, Osaka's coach Wim Fissette said clay is a surface that leads the inexperienced into self-doubt.

"If Naomi plays on hard court and she goes for the forehand winner and she misses, she will say, 'OK, next time I will make it,'" explained Fissette, who drew parallels with former charge Kim Clijsters' attitude to the surface. "But maybe on [clay] she will think, 'Oh, maybe I should have hit with a little more margin, maybe I should have done this.'"

As for grass, the uncertainty is in her feet rather than tactics. "She has expressed already she's a bit afraid of falling or slipping on the court," Fissette said.

Gallery: Winning a major from match point down

The caveat has caveats, though. In 2016, Osaka made her Roland Garros debut with a grand total of four career red clay matches under her belt. Osaka defeated the following year's champion, Jelena Ostapenko, in the first round and stretched Simona Halep to three sets in the third. (That 4-6, 6-2, 6-3 loss to Halep remains the only match Osaka has ever lost at a Grand Slam after winning the first set.)

Osaka's grass-court debut was the previous year, at the Surbiton ITF $50K. She reached the final, where she knocked off Hsieh Su-Wei and Anett Kontaveit before falling to Vitalia Diatchenko.

Indeed, the data set of Osaka's results on natural surfaces is still very limited. Since becoming a major champion, she has played only one season on them, in 2019.

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3. Jennifer Brady is here to stay

At the start of 2020, few predicted Jennifer Brady's rise. For all the power of the American's serve and forehand, at the age of 24 she had not beaten a Top 10 victory or reached a WTA final.

Since then, under the tutelage of coach Michael Geserer, Brady, 25, has outpaced all expectations. Before the tour shutdown, she had established herself as a much-improved upset threat, scoring victories over Ashleigh Barty, Elina Svitolina and Garbiñe Muguruza in the first two months of 2020. On resumption, Brady reached another level by winning the WTA champion in Lexington and becoming a Grand Slam semifinalist at the US Open.

And now ... a Grand Slam finalist. It's a series of results that suggest Brady is not just on a hot streak but a legitimate threat. 

Read more: Jennifer Brady's journey to the top

"I think I belong at this level," she said after the Australian Open final. "I think winning a Grand Slam is totally achievable. It's within reach."

Brady, a UCLA alumna, was the first collegiate Grand Slam finalist since Stanford's Kathy Jordan finished as the runner-up to Martina Navratilova at the 1983 Australian Open. And Brady isn't alone. University of Virginia graduate Danielle Collins reached the semifinals in Melbourne in 2019, and this year five ex-college players featured in the quarterfinals of the women's and mixed doubles competitions.

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4. Barty keeping things in perspective

Win or lose, Barty has a knack for taking the hot air out of post-match pressers, reminding the media that what really matters to her are her family and mental health. After losing to Sofia Kenin in last year's semifinals, Barty brought baby niece Olivia into the press conference and rejected the idea that she had felt the weight of expectation.

"I've just tried to go about my business the same every single day," she said at the time. "Nothing's really changed for me or my team. We're trying to chip away every single day to get better as people, to get better as tennis players."

Read more: Barty readies for the road after 'heartbreaking' loss

This year's loss from 6-1, 2-0 up against Karolina Muchova in the quarterfinals stung, though. True to character, Barty refused to catastrophize: "The sun will come up tomorrow. We go about our work again."

But she admitted that the result was "heartbreaking." Barty has made no secret of how much she enjoys playing, and being, at home in Australia. Her two most recent titles have come on home soil, at Adelaide in 2020 and the Yarra Valley Classic three weeks ago. After three consecutive showings in the quarterfinals or beyond of the Australian Open, lifting the Daphne Akhurst Memorial Cup in front of her home fans is surely a driving force for Barty. Her quest for it will be a compelling narrative to come.

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5. The elusive 24

Another Grand Slam, another deep run from Serena Williams - but still no 24th major title.

Still Williams, 39, turned up in Australia with renewed fitness and another iconic outfit, and treated viewers to some phenomenal tennis. Her fourth-round defeat of Aryna Sabalenka was one of the matches of the tournament. Williams' straight-set win against Simona Halep a round later was sweet revenge from the one-sided 2019 Wimbledon final.

Serena's quest came to a difficult end against Osaka in the semifinals, but it also marked the sixth time she has made the semifinals of a major since returning from maternity leave. That's only two shy of the highest career tally among all active players aged under 35. Victoria Azarenka and Halep have each made eight Grand Slam semifinals.

Match report: Serena takes out Halep

Williams' coach, Patrick Mouratoglou, downplayed the importance of the mission for 24. "I don't think she needs that validation," he said to the press. After a run that should have underlined her unique brilliance rather than being framed as a failure, he has a point.

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6. Muguruza, Sabalenka within striking distance

Two players should be leaving Melbourne feeling as though they're on the verge of a breakthrough. 

Last year, the Australian Open was the site of Garbiñe Muguruza's resurgence as an unseeded player, she stormed to her fifth major final. She has largely maintained that form, winning at least two matches in every event she has played except the US Open, which was her first following the tour shutdown. This year, Muguruza was almost untouchable during Australian swing, winning seven matches by dropping four games or fewer. In holding two match points over Osaka in the fourth round of the Australian Open, she also pushed the eventual champion harder than anyone else.

But Muguruza couldn't close out Osaka. The 27-year-old has not won a Grand Slam title since Wimbledon 2017 or lifted a trophy at any level since Monterrey 2019.

Match report: Osaka saves match points to beat Muguruza

The other player who came out on the losing end of a tough encounter was Aryna Sabalenka.  She fell to Serena 6-4, 2-6, 6-2 in the fourth round of of this year's Aussie Open. The Belarusian, who compiled a 15-match winning streak over the end of 2020 and start of 2021, has yet to reach the quarterfinals of a Grand Slam.

But landing Serena in her section was only the latest in a series of difficult draws for Sabalenka in majors. Some of her first-week losses have come to the likes of Amanda Anisimova and Victoria Azarenka. 

Photo by Tennis Australia/Natasha Morello

7. Health uncertainty for Kenin and Andreescu

Two former Grand Slam winners made early, but perhaps not surprising, exits. Bianca Andreescu, winner of the 2019 US Open, was playing her first tournament in 15 months. She was undone by Hsieh Su-Wei in the second round. Defending champion Sofia Kenin was overpowered by an in-form Kaia Kanepi at the same stage.

In a tearful press conference, Kenin admitted the pressure got to her. The following week, Kenin, 22, crashed out to unranked teenager Olivia Gadecki in her Phillip Island Trophy opener. Three days later, she revealed she had needed emergency surgery to have her appendix removed.

However, Kenin's resilience in the face of setbacks has been one of the trademarks of her career. Last autumn, she suffered a 6-0, 6-0 loss at the hands of Victoria Azarenka in Rome, only to turn around and reach the Roland Garros final in her next tournament.  

Read more: Andreescu starts new chapter

For Andreescu, who was returning from a meniscus tear in her left knee, there were no shortage of straight-forward matches. Eighteen of her past 28 completed matches have gone three sets, including four out of the five she played during the Australian swing. Her run to the Phillip Island Trophy semifinals was a positive sign after such a long lay-off.

But Andreescu had to withdrawal from this week's Adelaide event with a left leg injury. Let's hope this isn't a major setback.