Massimiliano Allegri insists Cristiano Ronaldo is "the future" of Juventus, but reiterated the forward's arrival was never going to guarantee success in the Champions League.
The Portugal international joined Juve for more than £100m in the summer, bringing with him a record of five Champions League titles in the last ten years.
However, the Italian side were stunned in the quarter-finals of the competition on Tuesday by Ajax, with even Ronaldo unable to prevent Juve slipping to a 3-2 aggregate defeat.
Allegri said: "I always said Ronaldo's arrival was not like math; Juventus plus Ronaldo wasn't necessarily the Champions League title. Football is not an exact science.
"Ronaldo is the future of Juventus. He arrived this season and he's an extraordinary player, he played very well this season and he will do the same next season."
While Juventus came up short in the Champions League, they are just one win away from securing their eighth successive Serie A title.
They host Fiorentina on Saturday, and Allegri said: "Luckily tomorrow we have the chance to win the title, and we must do it tomorrow.
"We need to get over the disappointment of the elimination in the Champions League. We need to accept that and move on, because we can't go back in time and we can't change the score.
"Looking for justifications or alibis is just stuff for those who can never win."