Underdogs Ecuador swept their Davis Cup qualifier against Japan on Saturday in a match played behind closed doors due to the coronavirus outbreak, while elsewhere Australia beat Brazil and Kazakhstan eliminated the Dutch.
The hosts took to the court in Japan's western Miki city without two star players - injury-hit Kei Nishikori and world No 48 Yoshihito Nishioka, who decided not to join his team to avoid a possible virus quarantine on his return to the United States.
Gonzalo Escobar and Diego Hidalgo outplayed home duo Ben McLachlan and Yasutaka Uchiyama 7-6 (7-3), 6-3 in the decider to give 27th-ranked Ecuador a 3-0 victory.
Uchiyama said it was hard to concentrate while playing in a nearly empty arena, "but I don't want to use it as an excuse."
A limited number of journalists and other spectators were permitted to enter the arena once they had their body temperature checked, with some organisers wearing facemasks.
John Millman was Australia's hero in Adelaide with a second fighting win in the singles, wearing down Thiago Monteiro 6-7 (6/8), 7-6 (7/3), 7-6 (7-3) in three hours and five minutes to give the home side a winning 3-1 lead.
The victory echoed his earlier come-from-behind three-set win over Thiago Seyboth Wild in Friday's singles.
Team skipper Lleyton Hewitt said it would be a weekend for Millman to remember.
"What a performance. That's what Davis Cup tennis is all about," Hewitt said. "Johnny had to come out and back up what he did on Friday."
"That's going to go down as one of the great weekends in his career."
Marcelo Demoliner and Felipe Meligeni Alves earlier kept Brazil alive in the tie with a gripping three-set win in the doubles.
The pair fought back to beat John Peers and James Duckworth 5-7, 7-5, 7-6 (8/6) in almost three hours to pull Brazil back to trail 2-1.
In Kazakhstan, Andrey Golubev and Aleksandr Nedovyesov crushed Dutch duo Robin Haase and Jean-Julien Rojer in the doubles 6-3, 6-3.
Haase had won the opening singles on Friday and stepped back on court in Nur-Sultan to face Alexander Bublik, ranked 69 places higher at 100th.
The Dutchman battled hard in the first set but subsided after losing the tiebreak, with Bublik winning 7-6 (7/4), 6-1.
The 12 winners from this weekend's qualifiers will join the 2019 semi-finalists - Canada, Britain, Russia and Spain - as well as wildcards France and Serbia for November's Davis Cup finals in Madrid.
Davis Cup qualifying results on Friday:
Australia 3 Brazil 1
Jordan Thompson (AUS) bt Thiago Monteiro (BRA) 6-4, 6-4
John Millman (AUS) bt Thiago Seyboth Wild (BRA) 4-6, 7-6 (7/0), 6-2
Marcelo Demoliner and Felipe Meligeni Rodrigues Alves (BRA) bt
James Duckworth and John Peers (AUS) bt 7-5, 5-7, 7-6 (8/6)
John Millman (AUS) bt Thiago Monteiro (BRA) 6-7 (6/8), 7-6 (7/3), 7-6 (7/3)
Kazakhstan 3 Netherlands 1
Robin Haase (NED) bt Mikhail Kukushkin (KAZ) 6-4, 6-7 (2/7), 6-3
Alexander Bublik (KAZ) bt Tallon Griekspoor (NED) 7-6 (7/4), 7-6 (7/4)
Andrey Golubev and Aleksandr Nedovyesov (KAZ) bt Robin Haase and Jean-Julien Rojer (NED) 6-3, 6-3.
Alexander Bublik (KAZ) bt Robin Haase (NED) 7-6 (7-4), 6-1
Japan 0 Ecuador 3
Emilio Gomez (ECU) bt Go Soeda (JPN) 7-5, 7-6 (7/3)
Roberto Quiroz (ECU) bt Yasutaka Uchiyama (JPN) 7-6 (7/4), 2-6, 7-6 (10/8)
Gonzalo Escobar and Diego Hidalgo (ECU) bt Ben McLachlan and Yasutaka Uchiyama (JPN) 7-6 (7/3, 6-3)
Croatia 2 India 0
Borna Gojo (CRO) bt Prajnesh Gunneswaran (IND) 3-6, 6-4, 6-2
Marin Cilic (CRO) bt Ramkumar Ramanathan (IND) 7-6 (10/8), 7-6 (10/8)
Hungary 1 Belgium 1
Ruben Bemelmans (BEL) bt Attila Balazs (HUN) 5-7, 7-6 (7/4), 6-4
Marton Fucsovics (HUN) bt Kimmer Coppejans (BEL) 6-2, 5-7, 6-4
Italy 2 South Korea 0
Fabio Fognini (ITA) bt Lee Duck-hee (KOR) 6-0, 6-3
Gianluca Mager (ITA) bt Nam Ji-sung (KOR) 6-3, 7-5
Germany 1 Belarus 1
Jan-Lennard Struff (GER) bt Ilya Ivashka (BLR) 6-4, 6-4
Egor Gerasimov (BLR) bt Philipp Kohlschreiber (GER) 4-6, 7-5, 7-6 (7/3)
Slovakia 0 Czech Republic 2
Jiri Vesely (CZE) bt Jozef Kovalik (SVK) 6-3, 7-5
Lukas Rosol (CZE) bt Andrej Martin (SVK) 6-4, 6-4
Austria 1 Uruguay 1
Dennis Novak (AUT) bt Martin Cuevas (URU) 6-2, 6-4
Pablo Cuevas (URU) bt Jurij Rodionov (AUT) 6-7 (7/9), 6-3, 7-6 (7/5)
Sweden 1 Chile 1
Mikael Ymer (SWE) bt Marcelo Tomas Vera (CHI) 6-2, 6-3
Alejandro Tabilo (CHI) bt Elias Ymer (SWE) 6-4, 6-3
Colombia 1 Argentina 1
Daniel Elahi Galan (COL) bt Leonardo Mayer (ARG) 6-1, 6-4
Juan Ignacio Londero (ARG) bt Santiago Giraldo (COL) 6-7 (6/8), 6-3, 6-2
USA 2 Uzbekistan 0
Reilly Opelka (USA) bt Denis Istomin (UZB) 6-2, 7-5
Taylor Fritz (USA) bt Sanjar Fayziev (UZB) 6-1, 6-2