Substitute Gonçalo Ramos struck a last-minute winner as Paris Saint-Germain became the first team to win three times away to Barcelona in European competitions with a 2-1 win at the Estadi Olimpic Lluis Companys.
Ramos sealed a Champions League comeback victory to the delight of PSG's former Barcelona boss Luis Enrique after Achraf Hakimi had exposed the hosts' high defensive line.
Ferran Torres had put Barcelona ahead inside 20 minutes to establish a new club record of scoring in 45 consecutive games.
But the reigning European champions were level by halftime as Senny Mayulu, 19, converted in fine fashion.