Novak Djokovic's Belgrade homecoming next month will see him up against Andrey Rublev and Dominic Thiem for the Serbia Open title.
With the tournament's entry deadline having passed, the tournament entry list has been confirmed with the world number one, as expected, topping it.
Rublev, who has already won titles in Marseille and Dubai this season, is the only other top-10 player in the field, while Thiem is aiming to play the event as part of his comeback from a wrist injury which has kept him out of the game since June last year. He is due to return to action in Monte Carlo the previous week.
Gael Monfils, Karen Khachanov and Cristian Garin are also among the direct entries, as is Aslan Karatsev, the man who upset Djokovic at last season's tournament.
Borna Coric will play on his protected ranking, while the last direct entrant is world number 74 Oscar Otte.
The event takes place from April 18-24.
Djokovic returned to the ATP world number one spot on Monday, regaining the top ranking from Daniil Medvedev, who held it for three weeks.
Having refused vaccination against COVID-19, the 20-time Grand Slam winner has been unable to play a full schedule so far this season, missing the Australian Open plus Masters 1000 events in both Indian Wells and Miami.
Medvedev will have the chance to return to the summit at the ongoing Miami Open but there is every chance the number one ranking will be in play for Djokovic in Belgrade.