Paris St Germain shrugged off the absence of Zlatan Ibrahimovic to inflict a first defeat on Barcelona under their new coach Luis Enrique with a thrilling 3-2 victory at the Parc des Princes.
Injury denied Ibrahimovic the chance to face his former club but PSG proved they are no one-man team as goals from David Luiz, Marco Verratti and Blaise Matuidi helped them take the spoils in Paris.
Barca responded with goals from their own star strikers Lionel Messi and Neymar but could not find an equaliser, with rising star Munir El Haddadi coming closest with an 85th-minute effort that hit the post.
The result sees PSG replace Barca at the top of Champions League Group F on four points, one more than the Catalan side.
Barca came into the match having won six of their seven domestic and European matches this season and were yet to concede a goal, but that record was brought to an end after just 10 minutes on Tuesday night.
Lucas Moura's free-kick into the area was brought down by Luiz near the penalty spot and, with Javier Mascherano unable to make a challenge, the former Chelsea centre-back swivelled to fire a low left-footed shot past Marc-Andre ter Stegen.
That was the first time Barca had trailed in a competitive match since April, but they were behind for barely 60 seconds before drawing level with a brilliantly-worked team goal.
Javier Mascherano, Neymar, Andres Iniesta and Messi were all involved in a clinical one-touch move, which was finished off by Messi steering Iniesta's return pass beyond Salvatore Sirigu.
That showed Barca at their brilliant best, and another moment of magic from Messi almost saw them take the lead in the 25th minute, with his clever scoop over the PSG defence finding the run of Neymar, but the Brazilian was just unable to keep his effort down.
Barca were unfortunate not to be in front, but instead they found themselves 2-1 down two minutes later as PSG scored from another set-piece.
Thiago Motta's deep corner tempted Ter Stegen off his line but the German could not reach the ball as it sailed over both him and Ivan Rakitic to the far post, where Verratti had the simple task of heading home.
There was no immediate response from Barca on that occasion, and it was to get worse for the four-time European champions at the start of the second half when they conceded a third goal.
This time it was not a set-piece but a well-worked move that led to the goal, with the home side slickly putting Gregory van der Wiel into space down the right and his brilliant low cross was turned home first time at the far post by Matuidi.
It was a lead that impressive PSG arguably deserved, but once again Barca hit back straight away to reduce the deficit once more.
Dani Alves' handing cross from the right was controlled in the area by Neymar and, without allowing the ball to hit the ground, the Brazilian side-footed a volley in off the far post.
With fresh hope of salvaging something from the match, Barca went in search of an equaliser but they were almost caught at the other end as Javier Pastore charged through and drew a low save out of Ter Stegen.
Barca sent on Munir and veteran playmaker Xavi - making a record-breaking 143rd appearance in the Champions League proper - as they sought a leveller.
However, the visitors could not find that third goal with Iniesta and Sandro firing wide, Jordi Alba denied by a goal-saving block while 19-year-old Munir hit the post from 25 yards.