France and Switzerland each have one foot in the Davis Cup final after taking respective 2-0 leads over the Czech Republic and Italy.
The French duo of Richard Gasquet and Jo-Wilfried Tsonga made good use of their home advantage at Roland Garros, taking complete control of the tie with a possible three rubbers still to play.
Gasquet overcame Tomas Berdych 6-3 6-2 6-3, while Tsonga had little trouble in getting the better of Lukas Rosol 6-2 6-2 6-3.
It was Gasquet's 10th Davis Cup singles win as the world number 21 converted six of his 10 break points and hit 33 winners.
"It was an incredible match for me and I'm very happy to win this match," said Gasquet, who was only announced as replacement for Gael Monfils 24 hours earlier.
"It was important to start well. I have a lot of pressure to play on that court. The crowd was unbelievable and I'm very happy."
Berdych, meanwhile, was dismayed at his own level of performance.
"It was my worst Davis Cup match but also Richard played well," he said. "The truth is I was not a competitive enough opponent for him, that's why the score looks like how it is.
"This is the toughest conditions for me, coming from fast hard courts to the clay. I definitely need more time but it was a good choice for France. I need to move on and get over it."
Tsonga needed just 91 minutes to dispose of Rosol, sending down 11 aces on his way to victory to put the defending champions on the brink of elimination.
Likely to join France in the final are Switzerland, with Roger Federer and Stanislas Wawrinka both having enjoyed straight-sets wins against Simone Bolelli and Fabio Fognini respectively.
Seventeen-time major winner Federer saw off world number 76 Bolelli 7-6 (7-5) 6-4 6-4, and he was relieved to have come through the encounter after a tight first set.
"I just stayed with him really," he said Federer. "I served well myself. It ended up going to the tie-break, which I thought was the right thing. In the tie-break, I really think I served well throughout. The margins were small in the first set.
"In the second set I was finally able to get the break; that broke the deadlock for me a little bit. I was able to play with the lead, which is always easier.
"I'm just happy overall how it went. It's important to get that first point and that was the most important part."
Following Federer's success, Wawrinka's 6-2 6-3 6-2 triumph over Fognini means Switzerland are well placed to reach their first Davis Cup final in 22 years.
Switzerland will have the chance to break that duck when Federer and Fognini take on Paolo Lorenzi and Andreas Seppi in the doubles on Saturday, while Monfils and Julien Benneteau will look to finish off the good work started by Gasquet and Tsonga when they come up against Radek Stepanek and Jiri Vesely.