Defending champions Spain crashed out of the Davis Cup in the World Group first round with defeat to Slovakia.
Karol Beck and Michal Mertinak beat Albert Costa and Rafael Nadal 7-6 (7-3) 6-4 7-6 (8-6) in Bratislava for an unassailable 3-0 lead.
Spain were without Carlos Moya, who has chosen not to play in the Davis Cup this year.
Croatia upped the pressure on the US with a doubles win from Ivan Ljubicic and Mario Ancic giving them a 2-1 lead.
Ljubicic, who beat Andre Agassi in the singles on Friday, and Ancic overcame American duo Bob and Mike Bryan 3-6 7-6 (10-8) 6-4 6-4.
Australia moved into the quarter-finals with a doubles victory put them 3-0 up against Austria.
Victories for Lleyton Hewitt and Wayne Arthurs on Friday had put Australia in command, but Arthurs and Todd Woodbridge struggled in the doubles.
The Aussies finally overcame Julian Knowle and Jurgen Melzer 4-6 6-3 2-6 6-4 7-5 after a 90-minute rain break.
Australia will now meet Argentina in the quarter-finals in July.
The South Americans clinched their place after David Nalbandian and Guillermo Canas put them 3-0 up against the Czech Republic with a 6-3 4-6 6-1 6-2 victory over Tomas Zib and Jan Hernych.
Switzerland pulled themselves back to 2-1 against the Netherlands, with Yves Allegro and Ivo Hueberger coming from two sets down to beat Dennis Van Scheppingen and Peter Wessels 5-7 4-6 7-6 (7/5) 7-5 9-7.
French doubles pairing Michael Llodra and Arnaud Clement were made to battle hard by Sweden's Jonas Bjorkman and Simon Aspelin but eventually came through 7-6 (7/5) 6-4 6-7 (4/7) 6-4 to give France a 2-1 lead.
Russia moved 2-1 ahead in their tie against Chile, with Marat Safin and Mikhail Youzhny combining to beat Fernando Gonzalez and Adrian Garcia 6-3 6-4 6-3.
Belarus took a 2-1 lead over Romania when Max Mirnyi and Vladimir Voltchikov beat Andrei Pavel and Gabriel Trifu 7-6 (7/3) 6-3 6-4.