The Serie A giants travel to the Nou Camp for their quarter-final second leg tonight (7.45pm).
Juventus head into the tie with an intimidating 3-0 aggregate lead.
Dybala bagged twice in their first meeting last week, while Argentina team-mate Messi was kept off the scoresheet.
Barca have recovered from an even bigger deficit in the competition this season against Paris Saint-Germain, but a comeback is unlikely tonight.
Paulo Dybala and Lionel Messi know each other well from their time playing for Argentina
The pair have spoken and Dybala is intent on Juventus stopping Madrid lifting the trophy
To make matters worse for the Catalan giants, who are in somewhat of a free fall at present, rivals Madrid progressed to the semis yesterday.
Bayern Munich were just edged out in extra time at the Bernabeu after a harsh Arturo Vidal red card and Cristiano Ronaldo hat-trick.
However, to stop Madrid inflicting more pain on Barca, Dybala has provided Messi with some assurances.
According to Spanish outlet Don Balon, the pair have spoken and Dybala is intent on Juventus stopping Madrid lifting the trophy in Cardiff next month.
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Paulo Dybala has promised Lionel Messi Real Madrid will not lift the Champions League trophy
Atletico Madrid joined their neighbours in the final four last night, with Juventus and Monaco favourites to join them.
And Dybala, who has been pursued ahead of the summer by both Barca and Madrid, wants to keep Lionel Messi happy.
The promise has been made so their relationship is not affected on a personal level by tonight’s Champions League outcome.
Dybala has huge admiration for his compatriot, although obviously also has his own aspirations of winning the competition.