Thiemo de Bakker of the Netherlands and Argentina's Leonardo Mayer were Monday's first-round winners at the Vegeta Croatia Open tennis event.
De Bakker cruised past Russian Dmitry Tursunov by a 6-3, 6-3 margin, while Mayer handled Albert Ramos of Spain, 6-1, 6-3.
This week's field is led by the top four seeds of Richard Gasquet, Andreas Seppi, Fabio Fognini and Alexandr Dolgopolov.
Fognini comes in with a career-high 10-match winning streak after winning his second ATP World Tour title in eight days on Sunday at Hamburg.
Dolgopolov, who won his first career ATP World Tour title here in 2011, is the only former champion in the draw.