MOSCOW (AP) U.S. Open champion Marin Cilic reached the quarterfinals of the Kremlin Cup after grinding out a 6-3, 3-6, 6-3 victory over Russian wild card entrant Evgeny Donskoy on Wednesday.
The second-seeded Croatian struggled at times on his way to victory in 1 hour 52 minutes, his first match of the tournament after receiving a first-round bye.
He next faces either sixth-seeded Tommy Robredo of Spain or Serbia's Filip Krajinovic.
Cilic has yet to qualify for the season-ending ATP Tour Finals in London and a good showing in Moscow could prove important.
There was an upset in the women's draw as second-seeded Ekaterina Makarova exited her hometown tournament in the second round, losing 6-4, 6-4 to Romania's Irina-Camelia Begu.
Begu next meets either Bulgaria's Tsvetana Pironkova or Moscow-born Serbian, Aleksandra Krunic.