ATP - Belgrade 2R start

Second round commenced in Belgrade.

2021 Serbia Open - an ATP 250 tournament, on Clay, in Belgrade, Serbia, 19-25 April 2021.

The event was last held in 2012 when Andreas Seppi (2) defeated Benoit Paire 6-3 6-2

It replaces the Hungarian Open, the final edition which was the 2019 tournament, won by Matteo Berrettini who defeated qualifier Filip Krajinovic 4-6 6-3 6-1

Marton Fucsovics, sixth seed, withdrew after the main draw was published due to a knee injury, and was replaced by lucky loser Roberto Carballes Baena.

Laslo Djere was instated as ninth seed and was moved to the spot previously occupied by Fucsovics in the draw.

Pablo Cuevas withdrew after the main draw was published due to an adductor strain, and was replaced by lucky loser Joao Sousa.

Emil Ruusuvuori withdrew after the main draw was published due to an elbow injury, and was replaced by lucky loser Taro Daniel.

Second round results:

- Novak Djokovic (1) defeated Soonwoo Kwon 6-1 6-3

- Miomir Kecmanovic (8) defeated qualifier Arthur Rinderknech 6-3 3-6 6-3

- Filip Krajinovic (5) defeated wildcard Nicola Milojevic 6-1 6-1

- Matteo Berrettini (2) defeated Marco Cecchinato 6-4 6-3