RIO DE JANEIRO, Feb. 20 (Xinhua) -- Five of the top six seeds, including defending champion Dominic Thiem, were eliminated in an upset-filled first round of the ATP Rio Open on Tuesday.

Austria's Thiem, the No. 1 seed, lost to Serbia's Laslo Dere 6-3, 6-3 while second seed Fabio Fognini of Italy fell to Canadian Felix Auger Aliassime 6-2, 6-3.

Italian Marco Cecchinato, the third seed who won the Argentina Open on Sunday, was ousted by Slovenia's Aljaz Bedene 7-5, 7-6 (1).

Fifth seed Joao Sousa of Portugal and Serbia's sixth seed Dusan Lajovic also crashed out of the ATP 500 event on the outdoor clay of the Jockey Club Brasileiro. Sousa was beaten 4-6, 6-3, 6-4 by Guido Pella of Argentina and Lajovic succumbed to Briton Cameron Norrie 6-2, 6-1.

Uruguayan Pablo Cuevas was leading fourth seed Diego Schwartzman of Argentina 3-0 in the first set when their match was suspended due to rain.