Italy take doubles to edge USA in Davis Cup quarter-final
"I am really happy, I am here with my 'brother'. We played really well," said Fognini, after the pair beat Jack Sock and Tommy Paul 6-4, 6-4.
Italy, shorn of their two top players, world number 15 Jannik Sinner and 16the-ranked Matteo Berrettini, eliminated an American team led by ninth-ranked Taylor Fritz and Francis Tiafoe who is in the top 20.
Lorenzo Sonego, ranked 45th, opened the tie by coming from a set down to beat Tiafoe 6-3, 7-6 (9/7).
Fritz levelled when he survived a tough first set to beat Lorenzo Musetti 7-6 (10/8), 6-3.
That set the stage for the first doubles match of the week, after the first two quarter-finals were both settled after the two singles rubbers.
Fognini and Bolelli, the 2015 Australian Open champions, broke in the ninth game of the first set and the seventh game of the second to win.
Italy, the only one of the eight nations in Malaga whose football team is not at the World Cup, were roared on by strong support.
"I'm really proud of my team and of this crowd," said captain Filippo Volandri.
"It's like we are in Italy! All the players did an unbelievable job. Even Matteo who couldn't play because of injury is here and Jannik is supporting from home."
USA captain Mardy Fish did not enjoy his Thanksgiving.
"No doubt that was a tough day." he said. "No doubt that they were the better team today."
"Their doubles, they played phenomenally well. They're a great team."
On Saturday, Italy, whose only Davis Cup title came back in 1976, will face Canada or Germany, who meet in the last quarter-final later on Thursday.
The other semi-final pits Croatia against Australia on Friday.