The Argentina winger, totally out of form for much of the season, celebrated his 29th birthday in style, rifling in an 18th-minute free kick and then skipping past two weak challenges before curling in a superb second from 25 yards out, ten minutes after the break.
Germany winger Julian Draxler continued his rich form since joining from Wolfsburg, smacking in the second goal late in the first half.
Top scorer Edinson Cavani, also celebrating his birthday, emphatically drilled home the fourth in the 72nd minute – his 34th goal of a rampant season. Unlike last season, he is no longer second fiddle to Zlatan Ibrahimovic and is playing like a free spirit.
Ibrahimovic’s departure to Manchester United last summer has given Cavani a new lease of life and Barcelona suffered as a consequence.
The noise level at Parc des Princes reached deafening proportions as the home fans watched in almost stunned disbelief as Barcelona cracked under waves of incessant pressure. The Catalan side were supposed to be the favourites in the round of 16 match, but the night turned into a damage limitation exercise, the way it does when weak sides are totally outclassed.
The way Barca lost their shape and composure was completely unbecoming of such a proud club.
Luis Enrique’s side was destroyed by a PSG side playing with feverish determination, desperate to prove they belong among Europe’s elite after falling at the quarter-final stage in each of the last four seasons.
This time it looks like the mighty Barcelona won’t even reach the last eight, after equalling their worst ever Champions League defeat, last achieved by Bayern Munich at the semi-final stage four years ago. In truth, it could easily have been worse as they were outfought, outrun and outclassed.
Barcelona’s celebrated attacking trident of Lionel Messi, Luis Suarez and Neymar failed to trouble the PSG defence and the result will put enormous pressure on Enrique, whose side trail Real Madrid in the Spanish championship and now face almost certain elmination from Europe.