MOSCOW (AP) Evgeny Donskoy of Russia upset sixth-seeded Borna Coric 6-4, 6-4 in the first round of the Kremlin Cup on Tuesday,
Donskoy, the world No. 118, only faced one break point against the 39th-ranked Croatian.
Uruguay's Pablo Cuevas, seeded fifth, was leading 6-1 against Pere Riba when his opponent retired with a right leg injury.
In the women's competition, last year's winner, Anastasia Pavlyuchenkova of Russia, held on for a 7-5, 0-6, 6-4 victory over Monica Niculescu of Romania. Pavlyuchenkova clinched her first title of the season in Linz on Sunday.
Two players in the hunt for a place at the tour finals, fifth-seeded Carla Suarez Navarro of Spain and sixth-seeded Karolina Pliskova of the Czech Republic, were to play separate matches later Tuesday.