There will be no fans at this year's Serbia Open, says event organiser Djordie Djokovic, brother of world number one Novak Djokovic.
The Serbia Open hasn't been held as a 250 event on the ATP tour since 2013 but Belgrade has stepped up with Hungary unable to host their 250 tournament.
It will be held as a men's and women's joint event.
‘I don’t understand’ - Djokovic and Medvedev call for matches to be moved due to Tokyo heat
This year, like many others, the tournament will be held behind closed doors.
"Unfortunately, there will be no fans this year as we're in a difficult situation with a lot of people contracting the virus on a daily basis," the ATP 250 event's organiser Djordje Djokovic told Serbia's Nova S television.
"It's a very difficult year for everyone and the restrictions have resulted in a lot injuries. Regrettably, Borna Coric and Stan Wawrinka have had to pull out but it's still going to be a very strong field.
"Apart from Novak, Dominic Thiem, Gael Monfis and Aslan Karatsev will enter the tournament, as will Serbia's Filip Krajinovic, Laslo Djere and Miomir Kecmanovic. A lot of top 30 players will be here."
The tournament stats on April 19 and runs through to the 25th.
'Okay!' - Surprised Djokovic gets asked for his shirt by opponent at the net
Djokovic cruises past Dellien in comfortable first round victory