Chelsea blew a two-goal lead as their defence of the Champions League got off to a breathless start in a 2-2 draw against Juventus.
Oscar looked set to enjoy a dream European debut with a stunning first-half double but the Italian champions ruthlessly exposed the holders' defensive deficiencies to snatch a draw at Stamford Bridge.
Arturo Vidal pulled a goal back before the break and, after Eden Hazard was denied what appeared a penalty, Fabio Quagliarella came off the bench to equalise and was a lick of paint from completing a sensational turnaround when his late effort clipped the crossbar.
Oscar, who had almost looked like he had been picked to shadow Andrea Pirlo, found himself in space 25 yards out and unleashed a drive that Gianluigi Buffon would surely have saved but for a telling nick off Leonardo Bonucci.
If the first was lucky, the second three minutes later was sublime, Oscar expertly controlling Ashley Cole's pass with his back to goal before spinning and unleashing an unstoppable dipping curler into the top corner.
But Juve are not 42 games unbeaten in Serie A for nothing. Claudio Marchisio almost broke through again and Vidal fired over before taking full advantage of slack defending to drive a low left-foot shot into the bottom corner. Hazard wasted another breakaway before half-time, after which Chelsea cranked up the pressure, with Branislav Ivanovic's dipping shot just kept out by Buffon.
The goalkeeper also beat away Frank Lampard's driven free-kick before the home side were denied a penalty when Hazard surged into the box and went down under a clumsy challenge from Barzagli. Referee Pedro Proenca simply told Hazard to get up and he arguably made another mistake when booking Ramires for a perfectly clean tackle.
Vidal deservedly saw yellow for hauling back Oscar but Juve were suddenly on top, Chelsea resorting to the sort of counter-attacking tactics that served them so well last season.
Ramires was withdrawn for Ryan Bertrand before Oscar - who was stood on making a tackle - departed for Juan Mata. Juventus responded by sending on Quagliarella for Sebastian Giovinco, who was actually looking a real threat.
And after Hazard and Mata almost combined to finish the contest - the latter blasting into the side-netting - the Juve substitute equalised. It was another defensive horror show from Chelsea, David Luiz hopelessly out of position as Quagliarella burst into an acre of space between John Terry and Ivanovic to steer Pirlo's through-ball between Petr Cech's legs.