The flag was spotted being held aloft as Ukraine’s Kateryna Baindl took on Russia’s Kamilla Rakhimova on Court 14 at Melbourne Park on Monday.
It sparked outrage on social media after Ukraine’s ambassador to Australia, Vasyl Myroshnychenko, demanded Tennis Australia take action.
“I strongly condemn the public display of the Russian flag during the game of the Ukrainian tennis player Kateryna Baindl at the Australian Open today,” Myroshnychenko wrote.
“I call on Tennis Australia to immediately enforce its ‘neutral flag’ policy.”
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Other tennis fans called the spectator’s act “disgusting”, while one wrote: “shame on Tennis Australia for allowing this”.
Former Australian ambassador to Ukraine Doug Trappett also called the incident “embarrassing” to Tennis Australia.
“You could have banned Russian players and positioned yourself to give a robust response to such predictable incidents but you chose spinelessness,” Trappett wrote.
“How painful for Ukrainians – incl. after atrocities by Russia in Dnipro yest.”
Tennis Australia has now revealed it will enforce a blanket ban on Russian and Belarusian flags in Melbourne Park, after initially allowing them onsite as long as they didn’t cause disruption.
“Flags from Russia and Belarus are banned onsite at the Australian Open,” Tennis Australia said in a statement to news.com.au.
“Our initial policy was that fans could bring them in but could not use them to cause disruption.
“Yesterday we had an incident where a flag was placed courtside.
“The ban is effective immediately.
“We will continue to work with the players and our fans to ensure the best possible environment to enjoy the tennis.”
Victoria’s Acting Premier Jacinta Allan threw her support behind the blanket ban on Tuesday, while describing Russia’s invasion of Ukraine as “abhorrent”.
“This is the right move. This is a good move from Tennis Australia,” Allan said.
“Russia’s invasion of Ukraine is abhorrent. It breaches international human rights obligations. It’s been enabled and supported by Belarus.
“This step is an important one. It sends a very, very clear message that human rights is important, whether it’s in sport or more broadly in our community.”
The crowd ban is in addition to a ban on tennis players from Russia and Belarus playing under the flags of their nations at the Aussie grand slam.
“Players from Russia and Belarus are only able to compete in international tennis events as individuals – and without flags or country recognition – which will be the case for Australian Open 2023,” Tennis Australia said.
“Tennis Australia stands united with the international governing bodies of tennis – the grand slams, the ATP and WTA Tours and the ITF – in its condemnation of Russia’s actions and its unprovoked invasion of Ukraine.”
Mr Myroshnychenko had previously called for Tennis Australia to ban Russian players from competing down under.
Wimbledon banned players from Russia and Belarus last year and in response, ATP and WTA penalised the Grand Slam tournament by stripping its ranking points.
It meant players who excelled at the event last year were not given a ranking boost.