Angel Di Maria struck twice in the Valentine's Day defeat, with Julian Draxler and top scorer Edinson Cavani scoring in between as the French champions carved out an impressive cushion ahead of the reverse fixture.
Unai Emery's men dominated proceedings for the entire 90 minutes as Lionel Messi failed to register a single touch in the opposite box in a Champions League game for the first time this season.
4 - No side has ever overturned a 4+ goal deficit to progress in the Champions League knockout stages. Massacre.— OptaJoe (@OptaJoe) February 14, 2017
No side has ever overturned a 4+ goal deficit to progress in the Champions League knockout stages, meaning Luis Enrique's men must break a record if they are to have any chance of winning the tournament.
PSG travel to Camp Nou for the second leg of the tie on March 8.