2021 Zagreb Open
Date	10–16 May 2021
Edition	17th
Surface	Clay
Location	Zagreb, Croatia
Champions
Singles
Sebastián Báez
Doubles
Evan King / Hunter Reese
← 2011 · Zagreb Open · 2022 →

The 2021 Zagreb Open was a professional tennis tournament played on clay courts. It was part of the 2021 ATP Challenger Tour. It took place in Zagreb, Croatia between 10 and 16 May 2021.

Singles main-draw entrants

Seeds

Country	Player	Rank1	Seed
ARG	Federico Coria	92	1
ESP	Pedro Martínez	95	2
SVK	Andrej Martin	109	3
JPN	Yasutaka Uchiyama	110	4
POR	Pedro Sousa	113	5
FRA	Benjamin Bonzi	115	6
BIH	Damir Džumhur	118	7
BRA	Thiago Seyboth Wild	126	8

• Rankings are as of 3 May 2021.^[1]

Other entrants

The following players received wildcards into the singles main draw:

• Borna Gojo
• Nino Serdarušić
• Antun Vidak

The following player received entry into the singles main draw as an alternate:

• Dmitry Popko

The following players received entry from the qualifying draw:

• Sebastián Báez
• Marcelo Tomás Barrios Vera
• Ernests Gulbis
• Ramkumar Ramanathan

Champions

Singles

• Sebastián Báez def. Juan Pablo Varillas 3–6, 6–3, 6–1.

Doubles

• Evan King / Hunter Reese def. Andrey Golubev / Aleksandr Nedovyesov 6–2, 7–6^(7–4).