Seeds Fabio Fognini of Italy and American Ryan Harrison came up first-round losers Tuesday at the $485,000 Serbia Open.
France's Benoit Paire took out the sixth-seeded Fognini 6-1, 6-4, while Brazilian Joao Souza subdued a seventh-seeded Harrison 6-3, 6-3 at MGM/Tennis Center Novak. Fognini was fresh off an appearance in his first-ever ATP final in Bucharest last week.
Another upset came when Czech Lukas Rosol dismissed fifth-seeded Pole Lukasz Kubot 7-5, 6-2, while eighth-seeded Luxembourg lefthander Gilles Muller avoided an upset by holding off Slovak Lukas Lacko 6-0, 4-6, 6-3. Kubot was the runner-up to Serbian hero Novak Djokovic in the inaugural Serbia Open in 2009.
Other Day-2 wins came for Argentine qualifier Eduardo Schwank, Romanian Victor Hanescu, Slovenian qualifier Aljaz Bedene, Croatian qualifier Antonio Veic and Spaniard Guillermo Garcia-Lopez.
Belgrade serves as a tune-up for the French Open and will pay its newest champ $88,000.