Italy beat Croatia in the doubles match to take a 2-1 lead in the Davis Cup first round on Saturday.
Fabio Fognini and Simone Bolelli took 3 hours, 17 minutes to beat Marin Cilic and Ivan Dodig 3-6, 6-1, 6-3, 7-6 (11).
Fognini converted Italy's fifth match-point with an ace in the tiebreaker.
Italy needs only one win from Sunday's reverse singles to advance to the quarterfinals for the first time since 1998, when it won the competition.
It would also be the first time Italy has beaten Croatia in three meetings.
Marin Cilic of Croatia will face Fabio Fognini of Italy in the opening rubber of their Davis Cup first-round tie on Friday.
Andreas Seppi, who has risen to a career-high ranking of 18, and Ivan Dodig will follow them.
Saturday's doubles pits Simone Bolelli and Paolo Lorenzi against Mate Pavic and Nikola Mektic.
The reverse singles on Sunday sees Seppi face 14th-ranked Cilic...
Draw for the Davis Cup first-round tie between Italy and Croatia on indoor clay at the Palavela:
Friday Singles Fabio Fognini, Italy, vs. Marin Cilic, Croatia
Andreas Seppi, Italy, vs. Ivan Dodig, Croatia
Saturday Doubles Simone Bolelli and Paolo Lorenzi, Italy, vs. Mate Pavic and Nikola Mektic, Croatia
Sunday Reverse Singles Andreas Seppi, Italy, vs. Marin Cilic, Croatia