(CNN) -- France are one victory away from reaching the Davis Cup final after winning both opening singles rubbers against Argentina in Lyon on Friday.
World number 30 Michael Llodra set the ball rolling for the home side with a 7-5 4-6 7-5 6-3 victory over Juan Monaco.
And France doubled their advantage when Gael Monfils -- the world number 15 -- secured an impressive 6-4 2-6 6-4 6-3 success over David Nalbandian.
The results mean that France can wrap up the tie on Saturday if Llodra and Arnaud Clement can defeat Eduardo Schwank and Horacio Zeballos in the doubles rubber, which would render the reverse singles on Sunday meaningless.
France, who knocked out holders Spain in the previous round, are playing their first semifinal since 2004 and Llodra told the official ATP Tour website: "I knew I had to stay focused and play my game.
"In the end, you know, it's tennis and anything can happen in Davis Cup. I eventually saved all the break points on my serve. It was a good match for me."
The winner of the semifinal will take on either Serbia or the Czech Republic, who are battling it out in the other last four clash.
Hosts Serbia suffered a major setback when world number two Novak Djokovic was forced to pull out due to a stomach illness.
And Radek Stepanek capitalized on Djokovic's absence to give the Czechs -- last year's beaten finalists -- a 1-0 advantage.
In a tough three-hour match, played in front of 17,000 partizan fans in Belgrade, Stepanek fought back from dropping the opening set to defeat Djokovic's replacement Viktor Troicki 4-6 6-2 6-4 6-4.