Juventus were without Cristiano Ronaldo, who tested positive for COVID-19 on Oct. 13, meaning a matchup pitting the Portuguese against Lionel Messi for the first time since 2018 would have to wait until at least the second group encounter.
Barca problem child Ousmane Dembele got the start alongside Messi and he rewarded Ronald Koeman’s faith early on with a goal from outside the penalty area to give the visitors the lead.
Juventus looked dangerous at the other end of the pitch as well and had the ball in the back of the net through Alvaro Morata right before 30 minutes, but the flag had gone up for offside and the goal was disallowed.
The teams returned from the half-time break with Barca still up 1-0 and Koeman making one change, substituting Ronald Araújo for Sergio Busquets due to an apparent injury.
Morata once again looked to have put Juventus back on level terms with a close-range strike, but once again the Spaniard was adjudged to have been offside after the match official consulted with VAR as Barca clung to their lead.
Barcelona continued to look dangerous in the attack, with Messi flashing a shot wide of the left post from the top of the area just after the hour mark and Pedri seeing his close-range attempt blocked minutes later.
Koeman made another change in the 66th minute, bringing on youngster Ansu Fati for Dembele with the Frenchman still working his way back to full match fitness.
The hosts’ hopes of getting back in the game took a big hit in the 84th minute when Merih Demiral was sent off after receiving a second yellow card to leave Juve with only 10 players to the match.
Messi then put the game away from the penalty spot after Fati was hauled down in the box to reach the final scoreline.