Roberto Di Matteo's team fail to hold on to two-goal lead as they begin Champions League defence in disappointing fashion following strikes from Vidal and QuagliarellaWayne Veysey at Stamford Bridge
Roberto Di Matteo called retaining the Champions League crown Mission Impossible. So it might prove, as his Chelsea began the defence of their title in unpersuasive fashion, surrendering a two-goal lead to draw 2-2 against Serie A flagbearers Juventus.
The aptly-named Oscar had threatened to steal the show with two goals in two minutes on his full Chelsea debut and in his first Champions League appearance, the second a strike of rare quality.
But Arturo Vidal gave his team hope with a fine strike shortly before half-time and substitute Fabio Quagliarella made the home side pay for a sloppy performance with an 81st minute equaliser.
Juve boss Antonio Conte, watching from the stands as he continues his lengthy touchline ban, had watched in dismay as his team wasted two gilt-edged chances midway through the first period but his well-drilled team eventually made amends.
Juventus' late comeback ensured a second consecutive night of high drama in the marquee Champions League fixture of the evening, although there was no Jose Mourinho-style knee slide to wrap up proceedings.
It is more than two decades since any club managed to retain Europe's grandest trophy – "because of the fierce competition," reckoed Di Matteo. "Every season there are new strong teams coming in like PSG and Juventus. It just has proved impossible for anybody to win it twice. But we will try to do the impossible."
Di Matteo made only a slight tweak to the team that stuttered to a draw at QPR, replacing Ryan Bertrand with the more exotic skills of Oscar, the £25 million signing from Internacional who has been gradually eased into life at Stamford Bridge following his exertions for Brazil at the Olympics.
It proved to be an inspired use of the considerable attacking midfield resources at the disposal of the Chelsea manager, who was unable to field a recognised striker on the bench following the late withdrawal of Daniel Sturridge with a hamstring injury.
Juventus returned to Europe's head table for the first time in three years as Serie A winners, league leaders and Italy's most convincing flag-bearers on the back of an astonishing 42-match league unbeaten run.
Just to rubberstamp their rejuvenation, the visiting starting X1 featured six members of the Italy team that began the Euro 2012 final against Spain – Gianluigi Buffon, Leonardo Bonucci, Andrea Barzagli, Girogio Chiellini, Andrea Pirlo and Claudio Marchisio.
Both sides struggled to create opportunities in the early exchanges, although David Luiz collected a nosebleed for his trouble after side-footing a fourth minute Frank Lampard corner straight at Buffon.
Juventus began to threaten on the counter-attack and twice came close to breaking the deadlock midway through the first period.
Firstly, Marchisio broke from midfield to spring Chelsea's off-side trap and latch on to a long pass from Barzagli but his first touch was too heavy and Petr Cech was able to smother the danger.
Soon afterwards, Branislav Ivanovic sloppy pass was intercepted and Mirko Vucinic was sent through on goal but the imposing No.9 biffed his shot wide.
Chelsea had been erratic up to this point, lacking composure in the final third and sloppy at the back.
But half an hour in, Oscar made his mark and demonstrated why he had been preferred to Juan Mata in the central playmaker role behind Fernando Torres.
Eden Hazard was once again the creator. The Belgian upped his already burgeoning assist count by swerving in from the left after 31 minutes and teeing up his sidekick in the centre. Oscar took a touch and then let fly from 25 yards, although Buffon would surely have saved the shot had it not take a cruel deflection off Bonucci.
If there was an element of fortune to Oscar's first goal for his new employers, the second was an absolute gem of imagination and execution.
With a single touch he was able to control the pass he received on the edge of the box and, at the same time, wrong-foot the defence to give himself a goal-shooting opportunity. The second touch was as glorious as the first, a delightful curled shot evading the dive of Buffon.
The home fans, who had already been pumped up by the Champions League trophy – or the 'Big Cup' as one noteworthy former manager calls it – being paraded shortly before kick-off, were in jubilant mood. "We know what we are, we know what we are, Champions of Europe, we know what we are," sang the faithful.
The vociferous visiting supporters, who had been momentarily silenced by Oscar’s sublime second, were soon back in full voice.
Chelsea switched off again in the 38th minute and this time they were punished by Arturo Vidal. The midfielder lashed a low shot beyond Cech from 20 yards to give his team hope going into the break.
Conte's team are famed for combining their physical determination with a willingness to attack and proved in the second period why they have become such tough nuts to crack.
Shortly after Oscar departed to a standing ovation from the home supporters, Quagliarella took full advantage of sloppiness from Mikel and a shocking attempt to play the off-side trap by Terry.
Mikel gave the ball away deep in his own half and Chelsea dawdled before Terry tried to deal with a deep pass from Marchiso by attempting to catch out Quagliarella. It failed dismally. The Italian darted past him and slotted calmly past Cech for a deserved equaliser.
It could have been even worse for the home side. With four minutes left, Quagliarella clipped the top of the bar following a delightful turn and shot.
A 3-2 victory for Juventus would have delivered a finish as improbable as that at the Bernabeu last night but, by dropping two points in a home fixture, Chelsea have given themselves a lot of work to do in a tricky group.