The 2021 Internazionali di Tennis Città di Trieste was a professional tennis tournament played on clay courts. It was the 2nd edition of the tournament which was part of the 2021 ATP Challenger Tour. It took place in Trieste, Italy between 26 July and 1 August 2021.

Singles main-draw entrants

Seeds Country Player Rank1 SeedDamir Džumhur1271Antoine Hoang1432Tomás Martín Etcheverry1663Danilo Petrović1734Alessandro Giannessi1775Marco Trungelliti1926Maximilian Marterer1967Thomas Fabbiano2028 1 Rankings are as of 19 July 2021.

Other entrants The following players received wildcards into the singles main draw: Flavio Cobolli Robin Haase Luca Nardi

The following player received entry into the singles main draw using a protected ranking: Julian Lenz

The following players received entry from the qualifying draw: Viktor Durasovic Pedro Sakamoto Timofey Skatov Thiago Agustín Tirante

The following player received entry as a lucky loser: Orlando Luz

Champions

Singles

Tomás Martín Etcheverry def. Thiago Agustín Tirante 6–1, 6–1.

Doubles

Orlando Luz / Felipe Meligeni Alves def. Antoine Hoang / Albano Olivetti 7–5, 6–7(6–8), [10–5].

References