Serbia, Australia, France and the United States all booked their places in the Davis Cup quarter-finals on Saturday, while defending champions Argentina kept their hopes alive in dramatic fashion.
Four of the eight first-round ties were wrapped up ahead of Sunday's reverse singles, with a Serbia team featuring Novak Djokovic among the nations to move into unassailable 3-0 leads.
Djokovic was not required for his country's doubles contest against Russia, as Viktor Troicki and Nenad Zimonjic earned a four-set win over Konstantin Kravchuk and Andrey Kuznetsov.
Australia and France each cruised to straight-sets wins to eliminate the Czech Republic and Japan respectively, while Jack Sock and Steve Johnson ensured a similar outcome for USA against Switzerland.
The remaining ties will all be decided on Sunday, Argentina having narrowly avoided falling 3-0 down to Italy in Buenos Aires.
Carlos Berlocq and Leonardo Mayer ultimately beat Fabio Fognini and Simone Bolelli 9-7 in a fifth-set tie-break, the home pairing having initially been pegged back from two sets up.
Argentina must win each of the remaining singles contests to reach the last eight.
Croatia hold the edge over Spain after the unheralded duo of Marin Draganja and Nikola Mektic earned a five-set win over Marc Lopez and Feliciano Lopez - two players ranked inside the top 12 of the doubles rankings.
Andy Murray was not missed as Great Britain moved 2-1 up on Canada, Jamie Murray - the brother of the absent ATP world number one - teaming up with Dom Inglot to beat Daniel Nestor and Vasek Pospisil.
Belgium are the other nation with a 2-1 lead after winning their doubles rubber against Germany.