The Serbian Open has returned to the ATP calendar this season with world No 1 Novak Djokovic the headline name. US Open winner Dominic Thiem is also set to attend the newly former ATP 500 event.
Belgrade played host to an official tournament between 2009 and 2012 but has dropped off the tour over the last nine years.
They are set to run concurrently with the Barcelona Open from the week commencing April 19.
Djokovic played a big role in helping to bring the Serbian Open back to fruition but it is his brother, Djordje, who is the tournament organiser.
To bring in greater sponsorships and to sell more tickets, competitions usually try their best to bring in the world’s leading players.
However, Djokovic’s long-term rival Federer was not sent an invitation because there are worries he would command a substantial fee.
But there are plans to reach out to the 20-time Grand Slam winner, if he holds off his retirement.
“We have not invited Roger this year because we had to consider our budget; we could not afford to spend all of our money on one player,” Djordje said.
“We had to distribute money the other way, to spread it, but we hope to see Federer in Belgrade in the coming years.
“It is my sincere hope that we will be able to host him at least once before he ends his career. We will invite him next year; I can promise that.”
“I want him to enjoy and behave like a player. Of course, he was involved in gaining the license, and he is enthusiastic about the event.
“I will surprise even him with some of the things we have in store for the players.”