Second-seeded Denis Istomin of Uzbekistan was eliminated in the first round of the St. Petersburg Open, losing to Lukasz Kubot of Poland 4-6, 6-3, 6-4 Wednesday.
Eighth-seeded Jurgen Zopp of Estonia advanced to the second round when Russian qualifier Andrey Kumantsov, trailing 6-3, 5-3, retired because of dizziness.
Igor Andreev of Russia, who was scheduled to face Sergiy Stakhovsky of Ukraine, withdrew because of a right shoulder injury. On Friday, Andreev retired because of the injury in the second set of the opening singles match against Brazil in the Davis Cup.
Stakhovsky then beat Russian lucky loser Ivan Nedelko 7-6 (2), 6-2, while Ricardas Berankic of Lithuania led 6-2, 3-3 when Philipp Petzschner of Germany retired with a right knee injury.
Results Wednesday from the St. Petersburg Open, an ATP event on indoor carpet at Peterburgksy Sports Complex (seedings in parentheses):
Singles First Round Jurgen Zopp (8), Estonia, def. Andrey Kumantsov, Russia, 6-3, 6-5, retired.
Lukasz Kubot, Poland, def. Denis Istomin (2), Uzbekistan, 4-6, 6-3, 6-4.
Simone Bolelli, Italy, def. Horacio Zeballos, Argentina, 7-6 (3), 7-5.