Despite an 83.40m performance from Bulgaria's Mark Slavov, Mardare responded with 83.60m with his fourth attempt.
Jiangsu sealed the win just three minutes later as Xie Pengfei converted a free kick and into the box and the ball hit at his teammate Li Ang, which created a rebound for Martins to score a volley.
Non-Japanese athletes should have tests within 72 hours before departure for Japan in their own country or region and will be tested again upon their arrival in Japan, according to the measures released after a joint meeting by Tokyo 2020, the Japanese government and the Tokyo metropolitan government.
Viera bagged his second with a stunning free kick in the 56th minute, before Cedric Bakambu added the fifth in the 85th minute.
The news came three days after the reigning champions suffered a 5-0 loss to Independiente del Valle in Ecuadorian capital Quito - the Rio de Janeiro side's worst ever defeat in the prestigious club competition.
In Rio de Janeiro, Botafogo recorded their seventh draw in 10 matches this season after a goalless affair with Santos at the Olympic stadium. The result left Botafogo 18th and Santos seventh.
In Friday's only other fixture, Bolivia's Jorge Wilstermann secured a 3-0 home win over Uruguayan side Penarol. Enditem
Yet, the fourth set became Jiangsu's one-sided show again as Gong Xiangyu made six kills and one block.
The 38-year-old broke the deadlock in the 34th minute as Theo Hernandez whipped in a cross from the left and the Swede out-jumped two defenders to steer his powering header into the net.
Dortmund responded with furious attacks but Gikiewicz was alert enough to keep out promising chances from Thomas Meunier and Erling Haaland before the break.
"Zlatan Ibrahimovic has tested positive for COVID-19 following a second round of swab tests ahead of tonight's game against Bodo Glimt," read a statement.