Defending champions Italy moved within one match of advancing past the United States to the Fed Cup semi-finals after victories by Karin Knapp and Camila Giorgi on Saturday.
World No.40 Knapp beat 62nd-ranked Christina McHale 6-3 3-6 6-1 in the opener, which lasted two hours and 14 minutes.
"It's incredible," Knapp said. "I'm really happy. I played a great match."
Camila Giorgi, ranked 84th, then downed 37th-ranked US teen Madison Keys 6-2 6-1 in only one hour in a matchup of Fed Cup debutantes.
The Americans have never recovered from an 0-2 deficit to win in the current Fed Cup format.
Keys, 18, is set to open Sunday's reverse singles against Knapp with the concluding doubles set to pit Italians Nastassia Burnett and Alice Matteucci against Americans Alison Riske and Lauren Davis.
Knapp blasted 30 winners to only 12 for McHale, the only US Fed Cup player with prior experience in the event.
Knapp had 57 unforced errors to 49 for McHale.
The Americans were without injured stars Serena Williams and Sloane Stephens while Italy lacked top names Sara Errani and Flavia Pennetta.
The Italians, who seek their fifth Fed Cup in nine years, beat the US women in the 2009 and 2010 Fed Cup finals and in last year's opening round.
Although the Americans own a 9-3 edge in their overall rivalry, they have not beaten Italy since 2003.
The winner will face either Spain of the Czech Republic in the semi-finals.
