Spanish veteran Rafael Nadal opened his Australian Open campaign Monday with a sweeping victory over world No. 66 Marcos Giron as the season's first Grand Slam finally began after a chaotic build-up dominated by Novak Djokovic's visa saga.

Defending women's champion Naomi Osaka breezed into the second round but teenager Coco Gauff and 2020 winner Sofia Kenin were early big-name casualties.

The 17-year-old Gauff was dumped out in straight sets by China's Wang Qiang, who is ranked outside the top 100. Kenin, on the other hand, was eliminated after a 7-6, 7-5 defeat by fellow American Madison Keys.

The only Australian Open champion in the men's draw after nine-time winner Djokovic's sensational deportation, Nadal started his quest to become the first male to win 21 Grand Slams by sweeping aside the 66th-ranked Marcos Giron 6-1, 6-4, 6-2.

There was relief from Nadal that they were at last playing tennis – he said he had grown "quite tired" of talking about his great Serbian rival, for whom he said he still has respect.

"The ideal situation in the world of sport is that the best players are on court, no?" said Nadal, who next plays Germany's Yannick Hanfmann in the second round.

"Honestly I wish him all the best. I think the situation has been a mess. He's not the only one that did probably the things bad."

Meanwhile, unvaccinated Djokovic landed in Serbia early Monday after his humiliating deportation from Australia, his dreams of a record-extending 10th Australian Open title ended for this year.

Clinical Barty

However, Ash Barty showed a good host can lift spirits at the most subdued of parties as she thumped Lesia Tsurenko 6-0 6-1 in a blistering start to her Australian Open campaign.

The home hero has been in rollicking form this season, capturing the Adelaide International title in the leadup, and carried it into her twilight match against the hapless Tsurenko at Rod Laver Arena.

Barty squandered two match points that would have handed Tsurenko the dreaded double-bagel and another two as she served for the match, but the Australian finally sealed it with a booming serve down the 'T'.

Barty will play Italian qualifier Lucia Bronzetti for a place in the third round.

It was business as usual for Japan's Osaka, who registered her 23rd win in her last 24 matches in the city of Melbourne, with a 6-3, 6-3 win against Colombia's Camila Osorio.

Seeded 13 after a disrupted 2021 season in which she said she had suffered "long bouts of depression," Osaka raced to a 5-0 lead before cruising through in 68 minutes.

"I would say I feel more comfortable in my skin, if that makes sense," said the 24-year-old, who won the title at Melbourne Park in 2019 and 2021. She will play American Madison Brengle in the second round.

"I just want to have fun, first of all. I can't expect myself to win every match, but I do expect myself to have fun and challenge myself."

Fourth seed Barbora Krejcikova of the Czech Republic, the reigning French Open champion, had little problem in blowing away Germany's Andrea Petkovic 6-2, 6-0 in 67 minutes.

The highest-ranked player to lose in the first round so far was Britain's 12th seed Cameron Norrie, easily beaten by American Sebastian Korda, the son of 1998 Australian Open champion Petr Korda, 6-3, 6-0, 6-4.

Jabeur withdraws

Tunisian ninth seed Ons Jabeur did not even make it onto the court.

She withdrew because of injury before her match against Spain's Nuria Parrizas Diaz and was replaced by lucky loser Irina Bara of Romania.

Italian seventh seed Matteo Berrettini, who reached his first Slam final at Wimbledon last year before losing to Djokovic, dropped a set before powering past American Brandon Nakashima 4-6, 6-2, 7-6 (7/5), 6-3.

There were also four-set wins for Canadian 14th seed Denis Shapovalov and Polish 10th seed Hubert Hurkacz.

Miomir Kecmanovic, who was originally drawn to meet Djokovic, had a much easier time against "lucky loser" Salvatore Caruso, winning 6-4, 6-2, 6-1 in 1 hour 56 minutes.

Germany's Tatjana Maria had the honor of striking the first serve in the tournament on the showpiece Rod Laver Arena before falling to Greece's Maria Sakkari, the fifth seed, 6-4, 7-6 (7/2).

"We all know how hard first rounds can be and that wasn't easy," said the athletic Sakkari.

Olympic gold medallist Belinda Bencic said she was still feeling the effects of COVID-19 a month after falling ill, as she moved into round two by overcoming Kristina Mladenovic 6-4, 6-3.

"I mean, my pulse was getting very up in the practices," she said.