Five-time champions Spain crashed out of the Davis Cup on Sunday when Canada completed a famous World Group triumph while 32-time winners United States edged Brazil in a dogfight.
Milos Raonic secured the crucial winning point in Canada's 3-2 victory in Vancouver by beating Guillermo Garcia-Lopez 6-3, 6-4, 6-2 to send Canada into their first Davis Cup quarter-final.
They will tackle Italy in April for a place in the semi-finals.
Missing top players Rafael Nadal, David Ferrer, Nicolas Almagro and Fernando Verdasco, Spain, winners of the title three times in the last five years, and the 2012 runners-up, had been 2-0 down on Friday.
Marcel Granollers and Marc Lopez kept their hopes alive with a 4-6, 6-4, 6-7 (4/7), 6-3, 6-2 victory over Daniel Nestor and Vasek Pospisil in Saturday's doubles.
But Raonic, the world number 15, was unstoppable on Sunday firing 22 aces and 55 winners past the hapless Garcia-Lopez, the world 82, as Spain were beaten in the opening round for the first time since 2006.
Albert Ramos beat Frank Dancevic 7-5, 6-4 in a dead rubber to create the final margin.
The United States escaped an upset when Sam Querrey rallied to beat Thiago Alves 4-6, 6-3, 6-4, 7-6 (7/3) and give the Americans a 3-2 triumph. Querrey fired 26 aces for a perfect weekend in his first Davis Cup home tie.
Brazil's Thomaz Bellucci battled back to defeat John Isner 2-6, 6-4, 6-7 (7/9), 6-4, 6-3, in Sunday's opener at Jacksonville, Florida.
Isner fired 22 aces in the clash but also committed 81 unforced errors.
The US had been 2-0 ahead on Friday before twins Bob and Mike Bryan suffered a stunning loss in the doubles - just the third of their Davis Cup career - to Marcelo Melo and Bruno Soares, going down 7-6 (8/6), 6-7 (7/9), 6-4, 3-6, 6-3.
The Americans will meet 2010 champions Serbia, who had already defeated Belgium.
Tomas Berdych beat Stanislas Wawrinka in a battle of Davis Cup ironmen as defending champions Czech Republic reached the quarter-finals.
The Czechs led Switzerland 2-1 overnight after Berdych and Lukas Rosol beat Wawrinka and Marco Chiudinelli 6-4, 5-7, 6-4, 6-7 (3/7), 24-22 in the longest-ever Davis Cup match, an exhausting doubles which lasted a minute over seven hours.
World number six Berdych and Wawrinka, the 17th-ranked player, returned on Sunday for the first of the reverse singles in Geneva and three hours 15 minutes later, it was the Czech who triumphed again, claiming a 6-3, 6-4, 3-6, 7-6 (7/5) win.
"Stan is one of the players who I don't like to play. He has a dangerous game," said Berdych, of a player who also featured in a five-hour defeat to Novak Djokovic at the Australian Open last month.
"The match on Saturday will go down in history. You play tennis for moments like this," added Berdych, who won all three rubbers he played this weekend and spent almost 13 hours on court.
Wawrinka insisted that despite his three matches -- he had also won his opening singles on Friday - he would have been able to play a fifth set on Sunday.
"I care about this competition and love to play for my country," said Wawrinka, who was Switzerland's top player in the absence of Roger Federer.
"We were really close. I was up in the tiebreak today but Tomas played better and showed why he is number six in the world."
The Czech Republic will now travel to Kazakhstan in April for the quarter-finals.
Kazakhstan, who beat Austria 3-1 in their World Group clash on Sunday in Astana, knocked the Czechs out in the first round in 2011.
In Turin, Italy beat Croatia to make the quarter-finals for the first time since 1998.
Italy had led 2-1 overnight but Marin Cilic won his second singles match of the tie by easing past Andreas Seppi 6-3, 6-3, 7-5.
Fabio Fognini then saw off Ivan Dodig 4-6, 6-4, 6-4, 6-4 to clinch the winning point.
"In Davis Cup, everyone wins or everyone loses...it wasn't just my victory, it was Italy's victory," tweeted Fognini.
The other quarter-final will see Argentina facing France after they completed comfortable victories over Germany and Israel respectively on Saturday.