The Spanish fullback joined Chelsea yesterday for €27 million.
“Our first objective was to keep our starters," Corvino explained in a Press conference today.
“Apart from Alonso, for whom we received an offer we couldn't turn down, we did."
He also remarked: "I don't know how many other clubs would have given up the money on offer for some players.
"Then there's Alonso's situation, but how could I say no?
"In recent seasons this club has made a very serious loss, close to €40m.
"In order to fall under the conditions imposed by Financial Fair Play and avoid penalties and fines, we weren't able to buy, we endeavoured to do what we did in this transfer window.
"I repeat, the club said no to many, many millions of Euros for players who we'll never be able to recover certain figures for. We've been consistent."
Asked about Paulo Sousa's attitude over the sale, Corvino continued: “The only thing is that we weren't prepared for the possibility of selling Alonso, but we never expected such an offer.
“Before saying yes to Chelsea, we racked our brains to replace Alonso and when I said [Maxi] Oliveira he told me 'I trust you'.
“Some might say 'but who is Oliveira', but that's a question by someone who doesn't know him. You can't value you him by how much was paid for him, that's not how you judge a player.
“Excluding Alonso we've held onto all of our important players and that's a good sign, and don't forget that we've signed some good prospects.
“This is a Fiorentina who can compete with anyone."