Tennis, with all its aging and ailing superstars, has been bracing for big farewells for years. But players like Roger Federer, Serena and Venus Williams and Andy Murray have defied the timeline and the expectations, pressing on and rejecting retirement through competitiveness, stubbornness, and a love of the game and the platform.

Which is why Wednesday came as such a surprise.

Ashleigh Barty, by these new-age standards, was just getting started. At 25, she was ranked No. 1 with three Grand Slam singles titles in the bank, including Wimbledon last year and the Australian Open in January. Already an icon at home, she had the beautiful game and winning personality to one day become a global brand as the majors and seasons piled up.

But Barty was on her own timeline, and, after long and careful consideration, she is retiring on top, the very top, which might sound neat and tidy but actually requires the self-awareness and the guts to leave quite a few things unfinished.

If Barty remains retired, she will never win a U.S. Open singles title, never win the Billie Jean King Cup team event for Australia, never win an Olympic gold medal, never, with her complete set of tennis tools, achieve the calendar-year Grand Slam that her Australian predecessors Rod Laver and Margaret Court won more than 50 years ago.

But there is more to a champion’s life than a checklist, and, as Federer and his enduring peer group would surely confirm, it is only worth making the trek to such low-oxygen destinations if you genuinely enjoy the journey.

Barty, a teen prodigy who won the Wimbledon girls title at age 15, has long seemed like someone whose gift took her farther than she wanted to go.

“I’m shocked and not shocked,” Rennae Stubbs, an Australian player, coach and ESPN analyst, said of Barty’s retirement. “Ash is not an ego-driven person wanting more. She’s happy and now comfortable and never has to leave her town and family again. And she’s content with her achievements now.”

The journeys, it is true, are longer for Australians, and they had been isolated under some of the strictest lockdowns and quarantine rules in the world during the pandemic.

Barty spent all of 2020 in Australia, opting to remain home in Brisbane rather than travel abroad to compete when tournaments resumed after a forced hiatus. She left the country for several months in 2021, cementing her No. 1 status by winning four titles, including Wimbledon. But after losing early in the U.S. Open, Barty, emotionally drained, returned to Australia and skipped the rest of the season.

That might have been a hint that early retirement was a possibility; that balance and personal well-being were Barty’s priorities, all the more so with her financial future secure. But then came her return to competition in January, when she ended Australia’s 44-year drought by winning the Australian Open singles title — without dropping a single set. After her forehand passing shot winner against the American Danielle Collins, she howled with delight.

Perhaps, in retrospect, it was a scream of relief. What looked like her latest achievement turned out to be her crowning one. She did not pick up a racket again, even to practice, after winning the title in Melbourne. She pulled out of the prestigious hardcourt events in Indian Wells and Miami, and then retired on Wednesday, delivering the news in a prearranged conversation with her friend and former doubles partner Casey Dellacqua that was released on social media.

“I don’t think Ash has ever been part of a current,” said Micky Lawler, the president of the Women’s Tennis Association, who spoke with Barty on Tuesday before her announcement. “This is not a new trend for her. I think she has always been very determined and very clear on where she stood and where tennis stood in her life.”

That clarity has been hard-earned. Barty has matured and learned a great deal about herself through therapy and life experience since she stepped away from the tour and its pressures for the first time at age 17, depressed and homesick. Sports comebacks remain all the rage, as Tom Brady continues to make clear. Tennis stars of the past who retired early — see Justine Henin and Bjorn Borg — did eventually return to competition, however briefly. But the feeling in tennis circles is that another Barty comeback is against the odds.

“I would guess that this is her final decision,” Lawler said. She added, “There would be a much bigger chance of her coming back if she lived in the States or in Europe. The fact she’s in Australia and loves Australia and loves being home, I think that plays a big role in how she decided this and when she decided this, and that will make a comeback that much harder.”

Lawler said that, in their conversation, Barty also made it clear that she did not want to continue placing travel demands on Craig Tyzzer, her veteran Australian coach.

Lawler said she expects Barty to request to be removed from the rankings, likely before the end of the Miami Open, which concludes April 3. No. 2 Iga Swiatek of Poland could become No. 1 by winning her opening match in Miami, but if she loses, No. 6 Paula Badosa of Spain could also become No. 1 by winning the title.

Though Swiatek, 20, and Badosa, 24, have powerful games and charisma, Barty’s departure leaves a void. Stylistically, her flowing, varied game was a refreshing change from the big-bang approach that has long prevailed. Barty, though she stood only 5-foot-5, had plenty of power and one of the most dominant serves — and forehands — in the game. But her success was also based on changes of pace, spin and tactics. She could hit over her backhand with two hands, or slice it with one hand and tremendous control, depth and bite.

Her full package often bamboozled more one-dimensional opponents. Other young players possess similar variety, including Russia’s Daria Kasatkina and Canada’s Bianca Andreescu, who won the 2019 U.S. Open. But Barty was the most consistent and irresistible exemplar of variety. She was 3-0 in Grand Slam singles finals, although it bears remembering that she never faced a player ranked in the top 10 in any of the Grand Slam tournaments she won.

That was no fault of her own, but her early departure will again make it challenging for the WTA to create what it has lacked for most of the last 20 years: the enduring, transcendent rivalries that have been the hallmarks of the men’s game in the age of Novak Djokovic, Federer and Rafael Nadal.

Serena Williams, the greatest women’s player of this era, is 40 and has not played since injuring herself in the first round of Wimbledon last year. She may not play again. Naomi Osaka, her heir apparent in terms of global profile and commercial portfolio, has struggled with her mental health and is now ranked 77th. Emma Raducanu, the talented British teen who was a surprise U.S. Open champion last year, is a sponsor magnet but not yet ready to soar to the top.

Perhaps Barty will take on other sporting challenges. During her first hiatus from tennis, she showed her potential to be a world-class cricketer, and she is an excellent golfer who is engaged to Garry Kissick, a professional golfer from Australia. Other women’s tennis stars have switched to professional golf, including Althea Gibson, but that move sounds unlikely given the global travel that sport also demands.

The WTA clearly knows how to crown champions and do business without Barty. Despite finishing the season at No. 1 the last three years, she has not been a dominant presence there amid her long breaks from the sport. But however well-considered her departure, it is still sad for tennis that she did not want to carry the torch forward.

Her character and game would have worn particularly well.