MELBOURNE, Australia (AFP) — Caroline Garcia and Andrey Rublev swept into the Australian Open second round on a blisteringly hot day Tuesday ahead of Novak Djokovic making his eagerly anticipated return to the season-opening Grand Slam.

Women's fourth seed Garcia and men's fifth seed Rublev both banked straight-sets wins before play was halted on outside courts and the roofs were closed on the main stadiums due to extreme heat.

Their victories came on a day when Tennis Australia banned Russian and Belarusian flags after a complaint from the Ukrainian ambassador to Australia.

The red, white and blue stripes of Russia were seen Monday during at least two matches, with Ukrainian fans reportedly calling security and police to the stands.

"The ban is effective immediately," Tennis Australia said.

Since the invasion of Ukraine, Russian and Belarusian players have normally competed under a neutral flag as independents, as is the case at the Australian Open.

Russia's Rublev ended the tournament of 2020 finalist Dominic Thiem 6-3, 6-4, 6-2 in 36 Celsius (96.8 Fahrenheit) temperatures.

Rublev held a clear advantage in terms of current ranking, but Thiem had a far greater Grand Slam pedigree as the US Open champion in 2020. He is also a two-time finalist at Roland Garros.

But the Austrian, ranked 98, was outplayed as he continued his return from a wrist injury which kept him off court for nine months across the 2021 and 2022 seasons.

"We are really good friends and I know he is going through difficult times, so I just want to wish him all the best to come back at the same level that he belongs to as fast as possible," Rublev said.

Garcia took just 65 minutes to overwhelm Canadian qualifier Katherine Sebov 6-3, 6-0 and cement her status as a contender for the first Grand Slam of the year.

Fifth seed Aryna Sabalenka also breezed through, beating the Czech Republic's Tereza Martincova 6-1, 6-4.

"I have to work on my mindset and stay calm and not get too upset when I make mistakes," she said. "I really believe this is the only thing missing in my game."

Women's 26th seed Elise Mertens was another winner, with the Belgian outlasting Spain's Garbine Muguruza, who was seen cramping before losing 3-6, 7-6 (7/3), 6-1.

Serbia's Djokovic, one of the finest men's tennis players of all time, was deported on the eve of last year's Grand Slam at Melbourne Park because of his stance on Covid vaccines.

But the 35-year-old will be back when he faces Roberto Carballes Baena of Spain in his opener and looks likely to be given a warm reception by the Rod Laver Arena crowd.

He is bidding to win the Australian Open for a record-extending 10th time and in doing so tie defending champion Rafael Nadal's men's all-time record of 22 Grand Slam crowns.

Djokovic is hot favorite for the first Grand Slam of the year, but after winning an Adelaide warm-up tournament last week, he has been bothered by a slight hamstring injury.

"I always like my chances. I train as hard as really anybody out there," Djokovic said ahead of his opener, attempting to dispel concerns about his hamstring.

Former world No. 1 and three-time Grand Slam champion Andy Murray will attempt to roll back the years.

The 35-year-old Briton faces Italian 13th seed Matteo Berrettini in a tantalizing match on day two at Melbourne Park.

Second seed Casper Ruud of Norway and 12th seed Alexander Zverev are also in action.

There were no major shocks on the first day, with Nadal grinding down promising Briton Jack Draper in four sets to launch the defense of his crown.

Tunisia's second seed Ons Jabeur, runner-up at Wimbledon and the US Open last year, starts her bid for a breakthrough maiden Grand Slam with a test against Slovenia's Tamara Zidansek.