HONG KONG, Jan. 2 (Xinhua) -- Top seed and defending champion Andrey Rublev of Russia suffered a surprising defeat to Hungary's Fabian Marozsan in the second round of the ATP Hong Kong Open on Thursday.

The world No. 8 fell to 58th-ranked Marozsan 5-7, 6-3, 3-6 after a match that lasted one hour and 58 minutes at Victoria Park.

Marozsan will face China's Shang Juncheng in the quarterfinals. 19-year-old Shang advanced comfortably, defeating seventh seed Pedro Martinez of Spain 6-3, 6-1.

In the day's other action, second seed Lorenzo Musetti of Italy triumphed over qualifier Gabriel Diallo of Canada, while Spain's Jaume Munar upset fifth seed Nuno Borges of Portugal 6-3, 7-5. ■