But, Switzerland's reign as Billie Jean King Cup champions is over after they suffered a second successive loss in Seville on Thursday, this time at the hands of the United States.
Danielle Collins used her experience to beat youngster Celine Naef 7-6, 6-1 before former Australian Open champion Sofia Kenin overcame Viktorija Golubic 6-3, 6-7, 7-5 to give her team an unassailable lead in the tie.
Kenin dominated the best part of two sets and was close to a straight-sets win before being dragged into a decider.
Three match points came and went at 6-5 on her serve but she kept her cool to finish the job and send the Swiss packing.
Last year's runners-up Australia edged Kazakhstan 2-1 in a must-win clash in Group B, although the complications of the group format mean they can no longer reach the last four.
Italy dispatched France on Wednesday and followed up strongly against Germany as Martina Trevisan secured a hard-fought 7-6, 6-1 victory over Eva Lys.
Paolini, who like Trevisan also won her singles against France, then dispatched Anna-Lena Friedsam 6-3, 6-2.
It is the first time Italy have reached the semi-finals of the competition since 2014.
"I think we have to rest tomorrow and be prepared for the next day. We've reached the semi-final which was a big goal for us," Italy captain Tathiana Garbin said.
"We have to be happy but never satisfied."
Australia had their backs against the wall after losing to Slovenia on Tuesday and needed to beat Kazakhstan to have any hope of reaching the semis.
Captain Alicia Molik changed her line-up and world number 155 Storm Hunter rewarded her faith by posting a 7-6, 6-4 victory against Anna Danilina, ranked a lowly 802nd.
Yulia Putintseva got the Kazakhs back in to the tie as she beat Kim Birrell 6-0, 7-5 and set up a doubles decider.
Doubles world number one Hunter then returned to court alongside Ellen Perez to take on Danilina and Putintseva and after splitting the opening two sets they held their nerve to win the match tiebreak 10-5.
Molik, who has been in the job a decade, initially seemed unsure of whether her team were out.
"I just wanted to triple cross-check with the referee's team. You're probably right (that we're out), but stranger things have happened."
Sadly for the Australians it was not enough and Kazakhstan will face Slovenia to decide the group winners.
