MELBOURNE, Australia — Ashleigh Barty plowed through the first two rounds of the Australian Open. No surprise there, as Barty, 24, is the top-ranked woman in the world. Except that Barty had a layoff of nearly a year before the run-up to the Australian Open because she opted not to leave Australia, her home country, for much of 2020 because of the coronavirus pandemic.

Nick Kyrgios, a folk hero of Australian tennis, similarly spent the past 11 months at home in Canberra, skipping two Grand Slam events and several other playing opportunities. He still captivated the tournament Wednesday night when he came back from two match points in the fourth set against Ugo Humbert, the No. 29 seed, and won it in the fifth in front of an electrified crowd. On Friday, he almost upset third-seeded Dominic Thiem, the reigning United States Open champion, but lost in five sets.

The success of Barty and Kyrgios, and that of some of their Aussie brethren, has lifted the spirits of Australian tennis fans who know too well the ongoing disruption caused by the virus, even in a country that has managed the pandemic arguably as effectively as any major economy in the world. Australian players passed up millions in potential prize money and several chances to play on the biggest stages in the sport, but have somehow come through in form.

“Absolutely no regrets for me,” Barty said this week as she prepared to play with the weight on her shoulders of her country and its 42-year Australian Open singles championship drought.

The difficult decision Barty and her fellow Australians faced is hardly settled, and players from other countries may feel similar pressures as travel restrictions change.

Australia’s government has said it plans to continue to require all passengers arriving from outside the country through the end of the year to quarantine in a monitored hotel room for two weeks.

For months, Canada has required people coming into the country to quarantine for two weeks, with the possibility of daily checks from the Royal Canadian Mounted Police. In January, Canada stepped up those restrictions and is requiring a three-night stay in a hotel room for all incoming air travelers while they await the results of a virus test.

The policies have forced a difficult choice on players from those countries: If they decide to play and endure all the international travel that professional tennis requires, they basically can’t go home until the end of the season in November — unless they choose to take a significant break.

No one has any good answers. Felix Auger-Aliassime, the 20-year-old Canadian who lists his residence in Monaco but still has deep ties to Montreal, said he is trying to figure out when he might be able to see his sister and his parents during the year. He did a two-week quarantine when he returned to Canada last year but isn’t sure when he might be able to manage one again.

Milos Raonic, another Canadian with a residence in Monte Carlo, said he is unlikely to play a full season. He said he saw his parents for just five days last year, rather than for months at a time as he would in a usual year.

“My family and those people that are close to me, they’re too important to neglect that aspect of my life,” Raonic said Wednesday after his second-round win over Bernard Tomic of Australia, whose tennis plans for the future are also somewhat up in the air.

“It’s not easy,” Tomic said after the loss. “If I leave Australia now, won’t be coming back anytime soon, for sure.”

Ajla Tomljanovic, one of the Australians who did play abroad last summer and fall, said the uncertainty of the schedule and the challenge of being away for so long had wreaked havoc with her game.

“I’m not looking further than tomorrow,” Tomljanovic said after a brutal loss to Simona Halep, the No. 2 seed. Tomljanovich won the first set and led 5-2 in the third, then lost five straight games. “Everything is such an unknown. Anything can change any second.”

That was partly what Barty, Kyrgios, Tomic, the former U.S. Open champion Sam Stosur and several other Australians figured last year when they passed on the revived tennis tours rather than deal with the uncertainty of the virus and the strict policies in Australia, which for months even limited travel between states.

Kyrgios notoriously has a love-hate relationship with the game. Tomic is trying to rebuild his once promising career at 28. Stosur, at 36, won her first match at the Australian Open since 2015. All said they did not touch a tennis racket for months, using the time away from the game as a reset. Stosur’s partner gave birth to a girl in June.

Barty gave up the most — the unique opportunity to play as the top player in the world and the chance to defend her French Open championship.

She spent little time keeping up with or following tennis.

“It was more enjoying my time at home and being grateful and appreciative for what I have,” she said.

She played a lot of golf. She attended Australian Football League matches and was famously photographed, beer in hand, at the A.F.L. final between Brisbane and Richmond. She got another dog, a Border collie.

Then, with Australia’s tennis season on the horizon, she got to work.

At first glance it is not obvious what makes Barty so effective. At 5-foot-5, she is built like a soccer midfielder and shorter than many of her elite competitors. She lacks the intimidating, blasting serve that several of the taller players in the top 20 have. She has powerful — though not overpowering — strokes.

There are few players who are more fit, though. She can defend every corner of the court on a point and rarely appears to be breathing heavily. On her shoulders and upper arms, her muscles appear to have muscles. She also mixes an unrelenting style with a complex, slicing backhand. She gives away little for free, even when she is aiming for the sidelines, which she does often, and she has a knack for finding an opponent’s weakness and picking it apart.

“Her tennis smarts are incredible,” said Daria Gavrilova, who lost to Barty on Thursday and has represented Australia with her on the national team. “Before a tie we always play team analysis, like the opposition analysis, and she’s always spot on. She’s just spot on every time.”

After the time away, Barty appears no worse for the lack of wear. She won her tuneup event last week, beating the two-time Grand Slam winner Garbiñe Muguruza in straight sets in the final, then began the Australian Open with a 6-0, 6-0 win.

While playing against Gavrilova, Barty wore a wrap around her upper left leg to support a muscle (ever the tactician, she refused to say which one). She insisted that the muscle soreness and the troublesome second set were not concerning or symptoms of rust.

“Lost my way a bit,” she said of a rocky portion of the match.

She appears to have found it, by following a surprising route, at least for now. She and the other Australians remain caught up in the nation’s remarkable Covid-19 success, which the country will not trifle with.

“You have to do what’s best for you and where you’re based and situated throughout the year,” said Lleyton Hewitt, the last Australian to reach No. 1 in the world rankings. “There’s a lot of outside-the-box thinking that has to go on to be an Australian tennis player right now.”