"It's a fantastic feeling; they played unbelievable all weekend. I'm very proud," Clement told reporters.
The result allowed France to wrap up the World Group first round tie with a day to spare and they will face Germany in the last eight in April after Tommy Haas and Philipp Kohlschreiber edged past Spaniards Fernando Verdasco and David Marrero 7-6(5) 6-7(9) 7-6(7) 6-3 in the doubles to go 3-0 up.
Spain paid the price for turning up in Frankfurt without world number one Rafa Nadal and David Ferrer and it was a similar story in Novi Sad, where a second-string Serbian team were swept aside 3-0 by Switzerland.
A day after putting Switzerland 2-0 ahead, a cheering Roger Federer and Stanislas Wawrinka leapt to their feet in celebration as Marco Chiudinelli and Michael Lammer beat Filip Krajinovic and Nenad Zimonjic 7-6(3) 3-6 7-6(2) 6-2.
The result put Switzerland into the last eight for the first time in 10 years.
"It's a dream outcome for us to win the tie on Saturday evening and we hope to have Roger Federer and Stanislas Wawrinka with us for the rest of the Davis Cup season," Swiss team captain Severin Luthi told a news conference.
DJOKOVIC HOPE
It completed a miserable weekend for the Serbs, who were runners-up to the Czech Republic only two months ago but now face a battle to preserve their World Group status in a playoff tie later this year after Novak Djokovic opted to skip the tie.
Serbia captain Bogdan Obradovic said he hoped world number two Djokovic would return for September's playoff.
"We need all our first choice-players back for that one, Djokovic most of all, but we also hope that Janko Tipsarevic will recover soon from his heel injury and that Viktor Troicki can rediscover his best form when he returns from suspension," he said.
The United States kept their fading 2014 title hopes alive when the world's number one doubles duo, Mike and Bob Bryan, beat Colin Fleming and Dominic Inglot 6-2 6-3 3-6 6-1 to trim Britain's overall lead to 2-1 on the red clay in San Diego.
However, Britain will be favoured to secure their first victory over the Americans in the competition since 1935 when Wimbledon champion Andy Murray takes on Sam Querrey in the first reverse singles match on Sunday.
World number 175 James Ward pulled off a shock singles win over 49th-ranked Querrey on day one to give Britain an unexpected 2-0 lead after Murray had crushed Donald Young, the replacement for the injured John Isner, in straight sets.
Champions the Czech Republic need to win only one of Sunday's reverse singles after Tomas Berdych and Radek Stepanek gave them a 2-1 lead with a 7-5 1-6 7-6(2) 7-6(4) win over Dutchmen Robin Haase and Jean-Julien Rojer.
Belgium, trailing 2-0 after the singles, made sure their tie against Kazakhstan would be alive on the final day after Olivier Rochus and Ruben Bemelmans secured a four-set win over Mikhail Kukushkin and Evgeny Korolev.
Japan also earned a 2-1 lead after Kei Nishikori and Yasutaka Uchiyama cast aside Canada's Frank Dancevic and Daniel Nestor 6-3 7-6(3) 4-6 6-4.
Italy nosed 2-1 ahead against Argentina after Fabio Fognini and Simone Bolelli hitback to defeat Eduardo Schwank and Horacio Zeballos 6-7(6) 7-6(8) 7-6(3) 6-4.
(Reporting by Pritha Sarkar, additional reporting by Zoran Milosavjevic and Mark Lamport-Stokes, editing by Josh Reich and Justin Palmer)
