ATP - Sofia 2R start

First round completed and second round commenced in Sofia.

2021 Sofia Open - an ATP 250 tournament, on Hard Indoor, in Sofia, Bulgaria, 27 September - 3 October 2021.

Event rescheduled last year to 8-14 November 2020 due to COVID-19.

Defending champion:

Jannik Sinner who defeated Vasek Pospisil 6-4 3-6 7-6(3)

Fourth seed Alexander Bublik withdrew after the main draw was published due to a shoulder injury, and was replaced by lucky loser Kamil Majchrzak.

Majchrzak received the first round bye previously given to Bublik.

First round results:

- James Duckworth defeated Emil Ruusuvuori 3-6 6-4 6-4

- Filip Krajinović (5) defeated wildcard Alexandar Lazarov 6-0 6-3

- Qualifier Illya Marchenko defeated qualifier Andreas Seppi 6-4 6-2

- Ilya Ivashka defeated Pablo Andujar 6-4 6-3

Second round results:

- Gianluca Mager defeated Miomir Kecmanovic 7-6(3) 6-3

- Lucky loser Kamil Majchrzak defeated wildcard Dimitar Kuzmanov 7-5 6-1