Paris St Germain made light of the absent Zlatan Ibrahimovic and a sub-standard start to the season to claim a 3-2 victory over Barcelona.
Barca had not conceded a goal this season but David Luiz, Marco Verrati and Blaise Matuidi punctured their defence to give the French champions three points.
Luiz put the home side ahead in the 10th minute only for Lionel Messi to equalise two minutes later at the end of a sharp move before Verrati's 26th-minute header put PSG in front again.
Matuidi caught the Barca defence snoozing again early in the second half and although Neymar pulled one back with a fine goal almost immediately, PSG held firm.
PSG lead Group F with four points, with Barca on three and Ajax Amsterdam third on two points after drawing 1-1 with Apoel.
PSG tore into a Barca side that had kept clean sheets in their first seven games in all competitions, making the Catalans look fragile at the back.
Talisman Ibrahimovic was ruled out of the tie with a heel injury, but PSG made up for his absence with Javier Pastore’s brilliance and Verratti’s grit.
PSG were rewarded for their early aggression when Luiz scored with a low shot on the turn from a Lucas free kick. But Barca quickly recovered with Messi sweeping the ball past Salvatore Sirigu after a fine one-two with Andres Iniesta, who was making his 100th Champions League appearance.
Barca cracked again when Verratti headed home from Thiago Motta’s corner.
Matuidi made it 3-1 nine minutes into the second half and on a high-octane night Neymar slotted a delightful shot in off the far post two minutes later but the expected Barca onslaught never really materialised.
Not even the 69th-minute introduction of Xavi, on for Ivan Rakitic, for a record 143rd appearance in the Champions League could earn Barca an equaliser.