Serbia is through to the Davis Cup quarter-final! Doubles team of Nenad Zimonjic and Viktor Troicki beat Andrey Kuznetsov and Konstantin Kravchuk 6-3, 7-6 (3), 6-7 (5), 6-4 to give 2010 champion Serbia an unassailable 3-0 lead against Russia in their Davis Cup by BNP Paribas first round tie in Nis on Saturday.