No club has ever overturned a first-leg 4-0 away defeat in a Champions League knockout tie (it has happened five times in the past).
The only time Paris SG eliminated Barcelona in the Champions League was in 1994/95 quarter-finals (3-2 on aggregate). Since then, Barcelona have won their two knockout encounters with the Parisian club (2012/13, 2014/15).
Barcelona's 4-0 loss in the first leg equaled their heaviest defeat in European competition. Their previous such-defeat came in the semi-final first leg against Bayern Munich back in 2012/13 - they lost the return leg 3-0 at home.
Barcelona have progressed past the round of 16 in each of the last nine seasons, the longest run ever in the competition. The last time they failed to reach the quarter-finals was in 2006/07 against Liverpool.
Paris SG have also gone past the round of 16 in each of their previous four campaigns but have subsequently been knocked out in the quarter-finals.
Barcelona have won their last 14 Champions League games at the Camp Nou (44 goals scored, 6 conceded), all since Luis Enrique took charge. Only Bayern Munich are on a longer winning run at home in the history of the competition (16, current streak).
Paris SG are winless in their four Champions League away games against Barcelona (D2 L2) but they have never conceded more than three goals in those four trips.
Edinson Cavani has scored seven goals in as many games in the Champions League this season, his best tally in the competition.
Lionel Messi, Neymar and Luis Suarez all played 90 minutes in the first-leg against Paris SG but none of them had a single shot on target.
Neymar has scored five goals in five games against PSG, his highest tally in the Champions League. He's the top goal creator in this season's competition with seven assists.
Unai Emery's team has progressed in their last 12 home/away knockout ties in Europe, all with Sevilla.