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.
Second seed Roger Federer, third seed Daniil Medvedev and wildcard recipient Andy Murray all play their second round matches later.
A number of outside court matches have been suspended by rain. Scheduled stadium matches have proceeded under the roof.