Serbia's Novak Djokovic returns to Italy's Jannik Sinner in a men's singles quarterfinal match on day nine of the Wimbledon tennis championships in London, July 5, 2022. (ALASTAIR GRANT / AP)

Novak Djokovic said he is preparing for the US Open as if he will be allowed to compete at the hardcourt major, despite his refusal to take the COVID-19 vaccine.

More than 43,000 people have signed an online petition calling for the United States Tennis Association to work with the US government to allow 21-times major champion Djokovic to compete in the US Open

Djokovic, who has three US Open titles, will not be able to participate at this year's US Open due to current rules under which travelers seeking to enter the US have to be fully vaccinated and provide a proof before boarding flights.

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Earlier this month, the 35-year-old was included in the entry list for the Aug 29-Sept 11 Grand Slam in New York. 

"I am preparing as if I will be allowed to compete, while I await to hear if there is any room for me to travel to US," Djokovic said in a post on Instagram along with a video of him practising.

"Fingers crossed!"

More than 43,000 people have signed an online petition calling for the United States Tennis Association to work with the US government to allow 21-times major champion Djokovic to compete in the US Open.

ALSO READ: Petition to allow Djokovic to play US Open nears 12,000 signatures

Djokovic won the Australian Open, French Open and Wimbledon titles last year but was unable to defend his Melbourne Park crown this year after being deported from Australia over his vaccination status in January.

The Serbian later said he was prepared to miss Grand Slam tournaments rather than take the COVID-19 vaccine.