The Old Lady's eight-point lead at the top of Serie A was cut down to three during that period, which also saw them eliminated from the Coppa Italia.
The goalkeeper insisted that he welcomes Napoli's challenge for the Scudetto, claiming that it motivates his side.
"It was a bit of a difficult time because analysing the games we did not win, you could tell we weren't in our best form," the goalkeeper told Sky Sport Italia.
"In January it all went wrong for us and we were a little complacent too. Now we are in the battle for the Scudetto and finally the opponents are revealing themselves, so we are not just challenging our own records. It's much more fun this way.
"It is very motivating to play knowing you cannot afford to get anything wrong. There are 15 games to go and everything is still up for grabs. I welcome more Scudetto rivals."
Juventus's 2-1 win over Chievo this afternoon restored their three-point lead at the top of the table.