He became a first-team regular under manager Renato Gaucho following the departure of Everton Soares to Benfica last month.
Medvedev will next face fellow American Frances Tiafoe, and Thiem will take on Canada's rising star Felix Auger-Aliassime.
"Additionally, several countries across the confederation have travel restrictions and quarantine requirements, which would make international football involving 30 national teams extremely difficult."
Both sides had chances to break the deadlock in the first half but missed them all.
Third seed Williams essayed a signature comeback and served 12 aces to edge past her American compatriot Stephens 2-6, 6-2, 6-2 in one hour and 43 minutes.
WASHINGTON, Sept. 3 (Xinhua) -- World number 77 Sorana Cirstea of Romania produced a sparkling performance to come from behind and beat No. 9 seed Johanna Konta of Britain 2-6, 7-6 (5), 6-4 in almost three hours to move into third round of the US Open on Thursday.
Kim Min-Jae (L) of Beijing Guoan vies during the 9th round match between Wuhan Zall and Beijing Guoan at the postponed 2020 season Chinese Football Association Super League (CSL) Suzhou Division in Suzhou, east China's Jiangsu Province, Sept. 6, 2020. (Xinhua/Li Bo)
Qingdao continue leading in the standings after nine games, with Ruichang ranking second by sweeping Shenzhen 5-0 on Sunday.
"We strictly followed the coach's match plan. This is a victory that belongs to the whole team since we played our football," said Saba. "As a forward, scoring goals is my responsibility."
"He did well in the most time of this match, I think Han deserves a reward,"
HOHHOT, Sept. 4 (Xinhua) -- The 2020 National Equestrian Competition kicked off on Friday in Xilinhot City, Xilingol League, north China's Inner Mongolia Autonomous Region.