Juve will attempt to salvage silverware from a disappointing season when they face Inter at the Stadio Olimpico on Thursday (AEST). The Nerazzurri beat Juve 2-1 in the Supercoppa Italiana back in January.
The Bianconeri's hopes of regaining the Scudetto have long since evaporated, with Juve 11 points behind leader Milan with two Serie A games to play.
It has at least secured Champions League football for next season, despite a run of form from Vlahovic that has seen him fail to score in any of the past four games in all competitions.
But Allegri is backing their marquee January signing from Fiorentina to fire in the final, while drawing a comparison with Ronaldo's slow start to life in Turin, which saw the Portugal star go the opening three Serie A games of his Juve career without scoring.
Asked in his pre-match media conference about Serbia national coach Dragan Stojkovic's prediction that Vlahovic would score in the final, Allegri said: "I hope he scores two! Not just one.
"Vlahovic is doing well and is serene. Sometimes he asks too much of himself. He is worthy of Juventus and he can improve next season.
"He has been scoring a decent amount of goals. In Italy, it isn't easy to score a goal per game.
"When Ronaldo arrived, he didn't score for five or six games. If Vlahovic looks upset, it means that he cares about what he does."
Luigi Delneri was the last Juve coach to end a season without a trophy, doing so in 2010-2011. Allegri is keen to avoid that fate at the end of a season impacted by Ronaldo's departure to Manchester United.
"The team had a bad start, but we reached an important result because playing the Champions League every season is crucial," said Allegri.
"We'll try to improve things and be ready to start again from next season.
"You all know that seeing Ronaldo leave with only three days remaining in the summer transfer window wasn't easy. I had to know the team as well. Then we lost Federico Chiesa.
"We faced a few difficult moments. On the other hand, we have improved and qualified for the Champions League round of 16. The club helped us by signing Dusan Vlahovic in January, but our run was stopped against Inter last month.
"Now I know the players and the staff, I am sure that next season we'll have more chances to win our main target, the Scudetto. It would be nice to win tomorrow, end the season in the best way and prepare for the next one."