Second seed Denis Istomin became the biggest casualty of this year's St Petersburg Open on Wednesday, losing his first-round match to Poland's world number 76 Lukasz Kubot.
The Uzbek took the first set but was eventually beaten 4-6 6-3 6-4 in just under two-and-a-half hours by Kubot, who goes on to meet unseeded Spaniard Damiel Gimeno-Traver in round two.
Third-seeded Slovakian Martin Klizan, who recently made the last 16 of the US Open, made it safely through with a 6-4 6-3 win over Mikhail Elgin of Russia, and fourth seed Fabio Fognini of Italy beat German Tobias Kamke 4-6 6-2 6-3.
Eighth seed Jurgen Zopp went through when opponent Andrey Kumantsov retired feeling dizzy while trailing 6-3 5-3, while there were also wins for Paolo Lorenzi, Simone Bolelli, Ricardas Berankis, Teymuraz Gabashvili and Sergiy Stakhovsky.
