Marin Čilić was the defending champion, but withdrew with a knee injury before the tournament began.
Tommy Robredo won the title, defeating Fabio Fognini in the final, 6–0, 6–3.

Seeds

The top four

seeds A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiosperm pl ...

receive a bye into the second round.

Draw

Finals

Top half

Bottom half

Qualifying

Seeds

Qualifiers

Qualifying draw

First qualifier

Second qualifier

Third qualifier

Fourth qualifier

References

Main Draw

Qualifying Draw
{{DEFAULTSORT:ATP Vegeta Croatia Open Umag - Singles, 2013 Croatia Open Umag - Singles

2013 Singles Thirteen or 13 may refer to: * 13 (number), the natural number following 12 and preceding 14 * One of the years 13 BC, AD 13, 1913, 2013 Music * 13AD (band), an Indian classic and hard rock band Albums * ''13'' (Black Sabbath album), 2013 ...