Defending champion Troicki, who beat Marcos Baghdatis in last year’s final, will play American Alex Bogomolov Jr. next. Bogomolov ousted Mikhail Kukushkin of Russia 6-4, 3-6, 6-4 to reach the quarters.
Russian Nikolay Davydenko eliminated his compatriot Teymuraz Gabashvili of 7-5, 6-2. Davydenko has won the Kremlin Cup three times.
The Russian former world no.3 will face Michael Berrer of Germany for a place in the semifinals. Berrer dismissed Italian Andreas Seppi 4-6, 6-3, 6-2.