Verdasco and Lopez retained Spain's 100% set winning record
Spain comfortably progressed to the quarter-final of the Davis Cup courtesy of a doubles win by Fernando Verdasco and Feliciano Lopez.
The Spanish pair took just over two and a half hours to beat Belgium's Steve Darcis and Olivier Rochus 7-6 (7-0) 6-4 6-3 to establish a winning 3-0 lead.
Spain will now face Chile or USA, with the Americans leading 2-1 in their tie.
Elsewhere, holders Serbia went 2-1 up against India after coming from a set down to win their doubles round.
Verdasco and Lopez's victory meant the Spaniards reached the last eight without dropping a single set.
On Friday, world number one Rafael Nadal returned from injury to make light work of Ruben Bemelmans, beating the Belgian 6-2 6-4 6-2.
This followed an earlier win for Verdasco against Xavier Malisse, whom he beat 6-4 6-3 6-1.
USA lead Chile after the world number one doubles pairing of Bob and Mike Bryan defeated Jorge Aguilar and Nicolas Massu with relative ease, 6-3 6-3 7-6 (7-4).
The American siblings breezed through the first two sets but trailed in the third when Bob Bryan's serve was broken in the fifth game.
The brothers broke back in the 10th game to even the score at 5-5.
The 3-0 score makes it look easier than it was
In the tie-breaker, Massu netted a forehand, sealing the USA's victory.
Andy Roddick will have the chance to put the tie out of Chile's reach when he faces Paul Capdeville on Sunday. Nicolas Massu will face John Isner if Capdeville manages to level matters.
Serbia's Nenad Zimonjic and Ilija Bozoljac came from a set behind to beat India's Rohan Bopanna and Somdev Devvarman 4-6 6-3 6-4 7-6 (10), putting the holders 2-1 up ahead of Sunday's reverse singles.
Twenty-six unforced errors by the Serbs in the opening stages allowed India to lead going into the second set,
However, Serbia broke early in both the second and third set to head to take the lead.
A dramatic tie-breaker saw Serbia miss a match point and defend a set point before taking the win.
"Psychologically, this was a very difficult match for us," said Zimonjic. "Now we're closer to winning the decisive point."
The winner will meet Sweden in the next round after Simon Aspelin and Robert Lindstedt added to Friday singles wins by beating Igor Kunitsyn and Dmitry Tursunov of Russia 6-4 6-7 (6-8) 7-6 (8-6) 6-2.
Austria inflicted a first doubles defeat in two years on France when Michael Llodra and Julien Benneteau were beaten by Jurgen Melzer and Oliver Marach 6-4 3-6 6-3 6-4.
The win means Austria have prevented early elimination from the tie after losing both singles matches on Friday.
Austria needed just one attempt at a break point to edge ahead in the first set and take the lead in front of a 5,000-capacity crowd in an aircraft hangar at Vienna's main airport.
An early break in the second set saw France pull the match level, but a solid display from Marach culminated in the 30-year-old winning the match with a forehand volley.
"The way we played was just perfect." said Marach.
Chela and Schwank's win took Argentina into the next round
France are missing their three highest-ranked players Gael Monfils, Jo-Wilfried Tsonga and Richard Gasquet who are all out with injuries.
In Sunday's reverse singles, Melzer will play Gilles Simon. If needed, Stefan Koubek and Jeremy Chardy will play the deciding match.
Austria have never beaten France in 77 years of Davis Cup history, and have never successfully turned around a 2-0 deficit. Likewise, France have never lost after being 2-0 ahead.
The victor will go on to play either Germany or Croatia.
Germany have the advantage after Christopher Kas and Philipp Petzschner outlasted Ivan Dodig and Ivo Karlovic to win the doubles 6-3 3-6 5-7 6-3 6-4.
Karlovic fired down a 251kph serve in the fourth set which surpassed the world record currently held by Roddick's 249.4kph effort in a 2004 Davis Cup tie.
Marin Cilic will be hoping to keep Croatia in it when he faces Philipp Kohlschreiber in the first reverse singles match on Sunday. If he succeeds, Dodig will Florian Mayer in a decider.
Argentine pairing Juan Ignacio Chela and Eduardo Schwank beat Romania's Victor Hanescu and Horia Tecau in straight sets, 6-2 7-6 (8-6) 6-1.
The win means Argentina march on to the next round with a 3-0 victory, allowing David Nalbandian to rest after suffering from a groin injury in his single win on Friday.
Nalbandian said he would have retired had his match been ATP tournament game.
"But Davis Cup is something special and the power one gets from it is something special," he said. "I never felt such pain on the court."
"I was very worried about the injury to David," said team captain Tito Varquez after his match. "But the 3-0 score makes it look easier than it was."
Argentina will face either Czech Republic or Kazakhstan.
The Czech Republic have a 2-1 lead after Tomas Berdych and Lukas Dlouhy beat Evgeny Korolev and Yuriy Schukin 6-4 6-4 7-6 (4).
Berdych will have the chance to continue his good work when he takes on Andrey Golubev in Sunday's first reverse singles tie.
Should Golubev win, Jan Hajek and Mikhail Kukushkin will play the deciding match.