Flavia Pennetta and Francesca Schiavone gave Italy a shock 2-0 lead over champions Russia, while the United States and the Czech Republic were level at 1-1 after day one in the Fed Cup semi-finals on Saturday.
Pennetta swept past an out-of-sorts Anna Chakvetadze 6-4, 6-0 in windy conditions at Castellaneta Marina before Schiavone fought back to beat Svetlana Kuznetsova 1-6, 6-2, 6-3.
Italy, the only nation apart from Russia to have lifted the Cup in the last five years thanks to their 2006 triumph, need to win just one of Sunday's three matches to reach the final.
"I'm half happy. I'll keep the rest of my happiness for tomorrow," Italian captain Corrado Barazzutti told Rai TV. "All three of the games we play tomorrow are going to be very hard."
After taking a scrappy first set, Pennetta started to play with assurance on the clay in the second and found little resistance from 22nd-ranked Chakvetadze, who was handed a singles berth after Vera Zvonareva pulled out injured.
The Russians, without new world number one Dinara Safina and third-ranked Elena Dementieva, looked on course to level the tie when Kuznetsova dominated the first set of her match at the southern Italian coastal resort.
But the world number nine seemed to rush the points and Schiavone took advantage to level the contest.
The Russian's error count piled up and the combative Schiavone was rewarded for never giving up, even after losing her serve at the start of the deciding set.
The US were expected to struggle in Brno since none of their top players had turned up for the tie and instead had to rely on two Fed Cup debutants spearheading the challenge in front of a noisy home crowd in the Czech Republic's second city.
Petra Kvitova predictably nudged the Czechs ahead with a 6-3, 7-6 win over Bethanie Mattek-Sands but Alexa Glatch unexpectedly levelled the contest by whipping Iveta Benesova 6-1, 6-2.
Mattek-Sands, who at 39th was the highest ranked US player in the team, had her chance to extend the match into a decider but was broken by the 19-year-old Czech and eventually surrendered in the tiebreak.
Glatch, ranked 114th, hit back by defeating Benesova, who is in the top 30, with surprising ease on the hard court in under an hour to keep things wide open.
"I thought I played pretty well and I'm just happy I could get a win for our team. I think we needed this one," Glatch told Czech Television.
"I played solid all around. I think I served very well then I used my slice pretty effectively. Those two things were key in the match."
The reverse singles matches take place on Sunday, when the ties will be wrapped up by the doubles encounters.