Holders Italy closed in on a third Fed Cup title in five years after taking a commanding 2-0 lead over an under-strength USA in the opening singles of the best-of-five match final on Saturday.
Italy's top player Francesca Schiavone gave the visitors a flying start by brushing aside untried American teenager Coco Vandeweghe 6-2 6-4 at the San Diego Sports Arena.
Flavia Pennetta then held off a first-set fightback by American number one Bethanie Mattek-Sands, saving one set point, before winning a tense match 7-6 6-2.
No team has come from 0-2 behind to win the Fed Cup and the Italians are poised to complete another whitewash against the Americans, having swept them 4-0 in last year's final.
Bhupathi-Mirnyi win, Bopanna-Qureshi lose
Valencia: India's Mahesh Bhupathi and Max Mirnyi of Belarus advanced to the men's doubles semis of the Valencia Open tennis, beating Frantisek Cermak of the Czech Republic and Michal Mertinak of Slovakia 6-3, 6-7(6), 10-6. But it was curtains for fourth-seeded pair of India's Rohan Bopanna and Pakistan's Aisam-ul Haq Qureshi who lost to Spaniards Marc Lopez and David Marrero 6-2, 6-4.