Roberta Vinci won a three hour, 13 minute marathon against Russia's Alexandra Panova as Italy grabbed a 2-0 lead in the Fed Cup final on Saturday.
A roaring home crowd backed Vinci as she was pushed to the limit before edging past Panova 5-7 7-5 8-6 in Cagliari.
Sara Errani kept up the momentum to record a more straightforward 6-1 6-4 win over Irina Khromacheva to put the hosts on the verge of their fourth Fed Cup title.
Italy are clear favourites to win the tournament against a Russian team who are contesting the final without top players Maria Kirilenko, Elena Vesnina and Anastasia Pavlyuchenkova.
Panova had four match points against Vinci while leading 7-5 5-2 but was powerless to stop Vinci, who played through severe neck pain, to win five games in a row to take the second set.
Vinci and Panova fought tooth-and-nail during a dramatic, error-strewn third set before the Italian wrapped up victory.