2021 Slovak Open II

The 2021 Slovak Open II was a professional tennis tournament played on hard courts. It was the 23rd edition of the tournament which was part of the 2021 ATP Challenger Tour. It took place in Bratislava, Slovakia between 8 and 14 November 2021.

Seeds

 * 1 Rankings are as of 1 November 2021.

Other entrants
The following players received wildcards into the singles main draw:
 * 🇨🇿 Jonáš Forejtek
 * 🇸🇰 Lukáš Palovič
 * 🇸🇰 Lukáš Pokorný

The following player received entry into the singles main draw as an alternate:
 * 🇩🇪 Tobias Kamke

The following players received entry from the qualifying draw:
 * 🇺🇦 Danylo Kalenichenko
 * 🇸🇰 Miloš Karol
 * 🇭🇺 Zsombor Piros
 * 🇨🇿 Dalibor Svrčina

The following players received entry as lucky losers:
 * 🇯🇵 Shintaro Mochizuki
 * 🇷🇺 Alexander Shevchenko

Singles

 * Tallon Griekspoor def. 🇭🇺 Zsombor Piros 6–3, 6–2.

Doubles

 * 🇸🇰 Filip Horanský / 🇺🇦 Sergiy Stakhovsky def. 🇺🇦 Denys Molchanov / 🇰🇿 Aleksandr Nedovyesov 6–4, 6–4.