Richard Gasquet and Pierre-Hugues Herbert beat Ruben Bemelmans and Joris De Loore 6-1, 3-6, 7-6 (2), 6-4 to give France a 2-1 lead over Belgium in the Davis Cup final on Saturday.
Gasquet and Herbert, who had never played together before, put France one win away from a 10th Davis Cup title. Belgium, in the final for the second time in three years, is seeking its first title.
In the northern city of Lille, the unexperienced French pair came out on top of a tense match with many ups and downs.
In Sunday's first reverse singles, Jo-Wilfried Tsonga can clinch the final for France with victory over Belgium's top player David Goffin. If Tsonga fails, the tie will be decided in the final reverse singles between Frenchman Lucas Pouille and Steve Darcis.
Despite their lack of practice and matches together, Gasquet and Herbert got off to a flying start on the indoor hard court at the Pierre Mauroy stadium.
Gasquet executed perfect passing shots from both sides and Herbert had a dominant presence at the net as the French pair broke for a 2-0 lead. A brilliant crosscourt forehand winner from Gasquet sealed another break for the hosts in the fourth game, with Goffin and Darcis looking ashen-faced in the stands.
Trailing 5-0, the Belgians saved two set points to finally hold their serve, but the respite was short lived as Gasquet served out the set in the next game.
A poor service game from Herbert put the Belgian pair back in the match early in the second set, though, when the doubles specialist hit a double fault and sent a volley long to hand their rivals a 3-1 lead. The hosts broke back but the French could not build on the momentum as their rivals finally got in the swing. De Loore fired a superb forehand passing shot in the next game and Gasquet dropped his serve after double faulting on break point. Bemelmans served out the set and the Belgian pair celebrated with a chest bump.
"They (Gasquet and Herbert) were on the brink of collapse," said France captain Yannick Noah. "In the end, it came down to just one or two points, and being focused."
The French were under pressure early in the third set and fought hard to fend off four break points in their first three service games. They finally cracked in the seventh game when De Loore unleashed a forehand return straight into Herbert's head to seal the break as he knocked the Frenchman to the ground.
Herbert quickly recovered as nervousness took hold of Bemelmans in the closing games of the set, with several misses on important points. The French pair made the most of his errors and leveled at 5-5 to the delight of the raucous home crowd with a break on his serve, before dominating the tiebreaker.
De Loore received treatment on his left foot before the start of a tense fourth set. A shaky Herbert hit two consecutive double faults to find himself trailing 15-40 on his serve in the sixth game, but the French managed to hold and made the decisive break for a 4-3 lead following another big mistake from Bemelmans, who buried a smash into the bottom of the net.