World's No. 1 men's singles tennis player Novak Djokovic of Serbia will not participate in the Miami Openbecause he failed to acquire the COVID-19 vaccination exemption, the tournament's director James Blake said on Friday.

"We tried to get Novak Djokovic to be allowed to get an exemption, but that wasn't able to happen," Blake told Tennis Channel. "Obviously, we're one of the premier tournaments in the world. We'd like to have the best players that can play. We did all that we could. We tried to talk to the government, but that's out of our hands."

According to the COVID-19 emergency declarations in the U.S., foreigners must be vaccinated before they are allowed to enter the country. This ban is expected to be lifted on May 11, but until then, unvaccinated Djokovic won't be able to go to the U.S..

Djokovic already missed last year's Australian Open and the ongoing Indian Wells Masters for the same reason. Ron DeSantis, governor of Florida, and two senators Marco Rubio and Rick Scott from the state, had been calling the Joe Biden administration to allow Djokovic to enter the U.S.

According to Djokovic's representative, the 35-year-old super star planned to compete in the Monte Carlo Masters clay-court event that will begin on April 9. Having won the Australian Open title in January, he matched Rafael Nadal in total Grand Slam championships (22). Both are expected to compete for their 23rd trophy in the French Open that will take place from May 23 to June 11.

As for the U.S. Open that will begin in late August, the U.S. Tennis Association believes it is "very hopeful" that Djokovic will enter the country and compete in the tournament.

"We are very hopeful that the policy preventing Novak Djokovic from entering the United States will be rescinded, or lapse, in the near future," spokesperson Chris Widmaier wrote to The Associated Press. "No COVID-19 restrictions are in place at the U.S. Open for any player, fan or other attendee. Novak, one of our sport's great champions, would be welcome to compete at the 2023 U.S. Open."