They beat L'Aquila Rugby with a + four points advantage in Round 1 of the tournament and now take on Leonessa on the two-leg quarter-finals.
Pedro Bravo, the Santboiana coach, said: "Everyone here - the players and staff - are thrilled with our result last weekend which put us through to the next round. It seems we have done the impossible!
"It was very tough physically for the players and they are tired but delighted with their performance and the result.
"However, Leonessa are a different proposition. The Italian Championship is of a better standard than the Spanish domestic competition and they will take our matches very seriously now that we have proved we are a good team - there will be no element of surprise.
"I would obviously have preferred to play the away match first but that's how it goes and you have to get on with it.
"A week doesn't give us much time to recuperate and get ready for the next match but the players are very motivated.
"It is very important for us to play these matches to gain experience to take forward to next season. We are learning a lot from these matches."But I think it will be very difficult for us to get good results against Leonessa. We will have to defend very well and force them to make mistakes."