Belgrade - Dusan Lajovic of Serbia and Ivan Dodig of Croatia advanced to the second round of Serbia Open on Monday.
Lajovic defeated fellow wild-card entry Evgeny Donskoy from Russia 7-5, 6-4, and Dodig used six breaks of serve to overcome Adrian Ungur of Romania 6-2, 6-7 (4/7), 6-4.
Serbian wildcard Marko Djokovic, the brother of top-ranked Novak Djokovic, lost 3-6, 1-6 to Filippo Volandri of Italy.
Novak Djokovic won his home tournament last year but pulled out of this week's event because of the death of his grandfather.
The Djokovic family organises the tournament.
Results on Monday from the Serbia Open on clay at Tennis Centre Novak (seedings in parentheses):
Dusan Lajovic, Serbia, def. Evgeny Donskoy, Russia, 7-5, 6-4.
Ivan Dodig, Croatia, def. Adrian Ungur, Romania, 6-2, 6-7 (4/7), 6-4.
Filippo Volandri, Italy, def. Marko Djokovic, Serbia, 6-3, 6-1.