Sixth seeded Tommy Robredo defeated Filip Krajinovic to setup an encounter with U.S. Open champion Marin Cilic while fourth seeded Fabio Fognini fell to Mikhail Kukushkin at the Kremlin Cup in Moscow on Thursday.

The 32-year-old Spaniard delivered 10 service aces and won 35 of his 37 first serves to defeat the Serbian in two straight sets 6-3 6-4.

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Robredo, who recently placed runner-up to Andy Murray at the Shenzhen Open in China, will now face off with Cilic in the quarterfinals.

The second seeded Cilic survived a three set scare from the Russian Evgeny Donskoy as he lost the second set to go to a deciding set where he was broken once by Donskoy but was able to break back twice to win the match 6-3 3-6 6-3.

Cilic is currently at the sixth position in the year-ending ATP World Tour Finals to be held in London this November. By virtue of winning the recent Grand Slam tournament, he has been given a slot in the eight-man short list.

Fourth seeded Fognini wasn't as fortunate as he lost his second round matchup against last year's runners-up Mikhail Kukushkin of Kazakhstan 6-4 6-2.

Both players exchanged breaks in the first set but Kukushkin was able to break another of Fognini's serve late and broke the Italian twice in the second set to record his second win over Fognini.

Kukushkin will go up against home crowd favorite Mikhail Youzhny who escaped a tie-breaking second set to win over Juan Monaco of Argentina.

The seventh seeded Youzhny dished out three service aces and won 71 percent of his serves to capture the second set after breaking Monaco twice in the first set to advance to the quarterfinals 6-3 7(8)-6(6).

Youzhny has won the tournament in 2009 against 2011 champion Janko Tipsarevic of Serbia. He was also a quarterfinalist in last week's Shanghai Rolex Masters where he was defeated by Spaniard Feliciano Lopez.

TagsMikhail Youzhny, Tommy Robredo, Marin Cilic, andy murray