This edition of the Gamper, a traditional festive occasion when Barca presents the squad for the upcoming season, proved a nostalgic affair. Just hours before the encounter, a tearful Messi bade farewell at a news conference after 21 years with the club, after Barca were unable to sign the player to a new contract.
Fans had hoped for a showdown between the Argentinian forward and Juve's Cristiano Ronaldo, with the two having won 11 Ballon d'Or trophies between them, but Messi's departure prevented that from happening.
Instead, there were tributes. Shouts of "Messi, Messi" could be heard prior to the game, attended by around 2,600 fans at the Johan Cruyff Stadium, and there were more in the 10th minute of the encounter, as a tribute to the club's most famous No. 10 and all-time leading scorer.
Fans also screamed Messi's name whenever Ronaldo touched the ball. The former Real Madrid player, who played the opening half in what was his first appearance in preseason, twice went close to scoring and clashed at one point with U.S. defender Sergino Dest.
Barca were missing several players due to injuries, including Sergio Aguero, who sustained a right calf injury in training and could face a spell on the sidelines. Eric Garcia and teenager Pedri, meanwhile, were absent as they have been competing with Spain at the Olympics.
Home coach Ronald Koeman fielded Memphis, Braithwaite and Antoine Griezmann in attack in a 4-3-3 formation and, despite the upheaval of Messi's exit, Barca looked further down the line in fitness and preparation than their rivals in what was their fifth game of preseason.
Barca took a third-minute lead with a fast counter-attack that saw Yusuf Demir set up Memphis and the Dutchman's left-footed strike beat Juventus goalkeeper Wojciech Szczęsny. Demir, 18, was continuing his fine preseason form and later won back possession inside the Juve area before whipping in a shot that was saved by Szczęsny.
Barcelona goalkeeper Neto was made to work either side of half-time. He kept out Alvaro Morata's powerful left-footed effort and fully stretched to push Ronaldo's 30-yard free kick to safety before the break, then denied Juve sub Federico Chiesa after the break.
The lead doubled in the 57th minute when a corner from Memphis was headed by Braithwaite past substitute goalkeeper Mattia Perin, who was beaten again in the final minute when substitute Puig turned inside the area to fire a left-footed shot into the top corner.
"It's not one of the best days," Barcelona defender Gerard Pique admitted after the game. "You know that you have to go through this day but the team was affected. Especially those of us who have spent more years sharing a dressing room with [Messi].
"At the level of talent and magic, it is not the same when the best in history goes away," Pique continued. "You lose a very important part in attack, someone that gave you a lot of goals and assists. We have to compete."
"Everyone knows what happened today and what we lost. It was not easy," Neto said. "There was a lot of emotion in the air but we are all professionals and we know that this has to continue. We have done what we had to do."
Also on Sunday, Barcelona's women's team, the current Champions League holders, scored five first-half goals and went on to beat Juve 6-0 and lift their first Gamper trophy.