SHANGHAI — Unseeded Andrey Rublev of Russia upset Borna Coric of Croatia 6-4, 7-6 (4) in the first round of the Shanghai Masters on Tuesday.
The 12th-seeded Coric was runner-up in Shanghai last year, losing to Novak Djokovic in straight sets in the final.
Two Americans – 16th-seeded John Isner and Reilly Opelka – are through to the second round.
Isner ousted Alex De Minaur of Australia 7-6 (1), 6-4, and Opelka defeated Dusan Lajovic of Serbia 6-3, 6-4.
Italy’s Matteo Berrettini, who reached his first Grand Slam semifinal at the U.S. Open last month, posted a 6-2, 6-1 first-round victory over Jan-Lennard Struff of Germany.
It was a 36th win of the season for the 11th-seeded Berrettini. He has won 30 of those matches since defeating Struff on April 22.
A number of outside court matches have been suspended by rain. Scheduled stadium matches have proceeded under the roof.