Brothers Bob and Mike Bryan made it 10 wins in 10 Davis Cup trips to give the United States, the record 32-time champions, a crucial 2-1 edge in their quarter-final against France in Monte Carlo on Saturday.
The Bryans cruised past Michael Llodra and Julien Benneteau 6-4, 6-4, 7-6 (7/4) to hand John Isner the opportunity on Sunday to wrap up the tie when the giant American takes on French number one Jo-Wilfried Tsonga in the first reverse singles.
Statistics do not favour the French as they have only come back to win on six occasions out of a possible 37 when they have trailed 2-1 going into the final day.
The French duo were so ineffective against the Bryans' serve that they won just five points in the first set, seven in the second and eight in the third.
"When you take American tennis in general, it's probably right to say that clay courts are not our best surface," said US captain Jim Courier.
"But today our players adored being out there. Just look at the way they played on Friday, see how confident John Isner was on clay.
"He has to play the same again on Sunday because Tsonga is a great player. We expect a reaction from the French. I am certain it will be a great battle and a very long day."
Tsonga had defeated teenager Ryan Harrison 7-5, 6-2, 2-6, 6-2 on Friday before Isner saw off Gilles Simon 6-3, 6-2, 7-5.
If Tsonga levels the tie Sunday, then Simon will tackle Harrison in the decider.
France captain Guy Forget insisted that Tsonga and Simon can turn the tie around.
"It's another day. We are playing on a surface which we selected in front of our own crowd. We are going to play and win," said Forget.
"Simon will beat Harrison. He is the number 13 in the world, playing on home clay, 10 minutes from where he grew up. He's facing a 19-year-old who is 66 in the world, He is not Nadal. Let's beat them."
The winner of the quarter-final will meet either defending champions Spain or Austria in September's semi-finals. The Spanish were 2-0 ahead after Friday's opening day in Castellon.
In Prague, the Czech Republic took a 2-1 lead over Serbia, who are without world number one Novak Djokovic, in their quarter-final after Radek Stepanek and Tomas Berdych breezed past Nenad Zimonjic and Ilija Bozoljac 6-4, 6-2, 7-6 (7/4).
Stepanek and Berdych won the 10th of their eleven Davis Cup doubles rubbers together, dominating the first two sets and coming back from 0-3 in the third set.
"We were a better team from the start," said Stepanek, who has won two doubles titles with India's Leander Paes this year -- at the Australian Open and last week's Miami Masters.
"We knew they would serve well, and we tried to return well and we managed to do that," he told the public Czech TV.
On Friday, Berdych swept Serbia's number two Viktor Troicki in straight sets, 6-2, 6-1, 6-2, while Stepanek lost a stormy epic five-setter to Janko Tipsarevic 7-5, 4-6, 4-6, 6-4, 7-9.
After Stepanek and Tipsarevic shook hands following Friday's tie, the Serbian number one accused the Czech veteran of aiming an obscene gesture at him and calling him names as they walked off to the sidelines.
On Sunday, Berdych, the world number seven, will take on eighth-ranked Tipsarevic while Stepanek, the world 24, meets 27th-ranked Troicki.
The teams last clashed in the 2010 Davis Cup semi-finals, which Serbia won before going on to lift their first title ever.
The winners will meet either Argentina or Croatia, who are 1-1 in Buenos Aires, in the semi-finals.