Defending champions Italy defied 40-degree temperatures to come back from 2-1 down to beat France 3-2 and reach the Fed Cup final.
The Italians will play Russia, who defeated the United States 3-2 in the second semifinal, which also came down to the final doubles rubber.
Francesca Schiavione, who remained unbeaten throughout the weekend, teamed up with Roberta Vinci in the crucial doubles to see off Nathalie Dechy and Severine Bremond 4-6 6-1 6-2.
Italy will now face Russia, who beat the USA 3-2, in the September 15-16 final.
France were left kicking themselves after throwing away a golden chance to wrap up the semifinal.
Amelie Mauresmo beat Mara Santangelo 6-7 (5/7) 6-0 6-4 in Sunday's opening singles before Tatiana Golovin threw away a 5-2 final set lead to crumble to a 6-4 2-6 7-5 defeat against Schiavone in the second singles rubber of the day.
Golovin became increasingly agitated with the passionate local crowd and made her irritation obvious.
"She got angry and I don't understand it," said French captain Georges Goven. "She was nervous and the match went down the tubes. It's the first time I have seen her in that situation. It was a costly mistake."
Schiavone was included in the doubles team despite having spent 2hr 44min on court against Golovin taking the place of Santangelo.
Golovin gave France their first point of the tie when she beat Tathiana Garbin 6-3 2-6 6-2 in Saturday's opening rubber before the home side hit back when Schiavone beat Mauresmo in straight sets.
On Sunday, Santangelo gave it her best in the first set against Mauresmo immediately putting the former world number one on her back foot, who only took the lead in the seventh game at 4-3 converting the first break of the match.
However, the French number one failed to keep her nose in front and eventually lost the tie-break despite winning the first five points.
Letting go of the first set seemed to wake Mauresmo up and the former Wimbledon and Australian Open champion came back in the second set, demolishing her rival 6-0 in just 25 minutes.
Following an obligatory ten-minute break due to the searing heat, Mauresmo got off to a bad start in the third set but recovered well to take the rubber.
In Stowe, Vermont, Nadia Petrova and Elena Vesnina overcame doubles standout Lisa Raymond and Wimbledon champion Venus Williams 7-5 7-6 (7/1) to secure Russia's place in the final.
Williams was a last-minute addition in the do-or-die doubles, but to no avail.
She had already delivered two points for the United States, including a quick 6-1 6-4 victory over Anna Chakvetadze yesterday that put the Americans 2-1 up.
But Petrova responded with a 6-1 6-2 victory over inexperienced Meilen Tu to knot the tie at 2-2.
After heavy rain delayed the start of play, Williams powered to an early lead in the first set as Chakvetadze struggled with her serve, coughing up seven double faults.
Chakvetadze steadied herself in the second, but still couldn't manage to break the US veteran.
It was an easy win for Williams compared to Saturday, when she endured a nightmare match against Petrova but eked out a 7-6 (8/6) 0-6 6-4 win that saw the Americans finish the opening day level at 1-1.
Chakvetadze had opened the tie with a 6-1 6-3 victory over 18-year-old American Vania King, who was replaced by Tu in yesterday's singles and then by Williams in the doubles as US captain Zina Garrison sought in vain to find a formula that would bring the Americans to the Fed Cup final for the first time since 2003.
They have not won the women's nations tournament since 2000.
Garrison had to make do this week without Serena Williams, who is nursing a hand injury suffered at Wimbledon.
Russia, who have won two of the last three Fed Cup crowns, were also missing some big names, with reigning US Open champion Maria Sharapova and Svetlana Kuznetsova sidelined by injuries.