Ryan Harrison of the United States lost 6-3, 6-3 to Joao Souza of Brazil on Tuesday in the first round of the Serbia Open.
Benoit Paire of France beat sixth-seeded Fabio Fognini 6-1, 6-4. Eighth-seeded Gilles Muller downed Lukas Lacko of Slovakia 6-0, 4-6, 6-3, and Guillermo Garcia-Lopez topped Igor Kunitsyn 7-6 (4), 6-7 (1), 6-2.
Victor Hanescu, qualifier Aljaz Bedene, Antonio Veic and Eduardo Schwank all won.
The tournament is organized by the family of top-ranked Novak Djokovic, who is sitting out the tournament after the recent death of his grandfather.