Shakhtar Donetsk 2 Chelsea 1: Chelsea are facing a battle to avoid becoming the first holders of the Champions League to fail to progress beyond the group stages after a woeful defeat in Donetsk.
Roberto Di Matteo's side are in danger of creating the wrong kind of history, having lifted the trophy in May, as they were replaced at the top of Group E by their talented opponents.
As it turned out, captain John Terry's presence on the pitch was the least of Chelsea's problems, although they were given an unlikely boost by Juventus's failure to win in Nordsjaellend, which keeps the Italian side one point behind.
But Chelsea's next two games are against Shakthar at home and Juventus away and, on this form, they are in a perilous position.
Chelsea knew before kick-off that they faced a difficult task to keep Terry or Frank Lampard from making the headlines no matter what took place.It was inevitable that their veterans would make an impact given the significance of the occasion for both of them, albeit for altogether different reasons. Terry was making his first appearance since deciding not to appeal his four-game ban from the Football Association for racially abusing Anton Ferdinand. This was supposed to be a happier outing for Lampard though as he became the first Chelsea player to reach 100 games in European competition.
Managers don't normally change a winning side, but Di Matteo turned to his two most senior players to cope with the considerable challenge Shakhtar were always going to provide and dropped Eden Hazard and Gary Cahill from the side that won convincingly at Tottenham.
This was supposed to be Terry's chance to make a more positive contribution to Chelsea's season after all the turmoil of recent weeks, while Lampard was hoping to use his personal landmark to also show he can still be part of this exciting new side.
Shakhtar clearly hadn't read the script though and unfortunately both of them made a telling negative contribution to the opening goal inside three minutes.
Lampard was the guilty party to begin with, giving the ball away carelessly to Darijo Srna. As Shakhtar advanced towards Petr Cech's goal, Luiz Adriano's shot rebounded off the outstretched arm perfectly into Brazilian midfielder Alex Teixeira's path and he calmly found the net.
Given that the home side came into the game boasting an unbeaten record lasting 28 games, it was a terrible possible start.
Chelsea struggled to regain their composure, with Tottenham target Willian sending a dangerous shot just over. Lampard then pulled up lame with less than 18 minutes on the clock. Hazard replaced him, but the change in personnel didn't lead to an improvement in what was arguably Chelsea's worst opening 45 minutes in a game this season, although Terry did start to make some telling interventions.
But for Cech, the visitors could have been out of the game before the break as the calamitous defending continued in front of him.
The goalkeeper tipped Henrik Mkhitaryan's shot over the bar and also had to be at his best to stop Tomas Hubschman's shot from close range, following Chelsea's woeful attempts to clear from a corner. There was little room for encouragement going forward for the visitors as Fernando Torres, who has yet to score in the competition this season, was ineffective.
Andrei Pyatov had little to trouble him in the Shakhtar goal and Chelsea's first-half showing was summed up when David Luiz's attempt to make a clever header back towards Cech went out for a corner.
The question was whether Di Matteo could say anything during the interval to inspire a dramatic change. Unfortunately the Italian was quickly given an answer in the negative.
If the sight of the hapless Torres seeing his shot rebound to safety off his own team-mate Oscar wasn't bad enough, Chelsea conspired to contribute to their downfall once again.
Hazard's pass was easily cut out by Adriano who was able to run unopposed towards the area before setting up Brazilian forward Fernandinho to double the home side's advantage seven minutes after the break.
Such was their dominance, home supporters took time out from watching the game to pose for photographs for a souvenir of an historic victory.
Even the sight of Pyatov making routine saves from Hazard and Ramires could not put a dent in the the players' confidence and it seemed a question of how many more goals.
Chances continued to come their way as Chelsea pressed forward and left themselves vulnerable to the counter attack, but Shakhtar almost paid the price for being wasteful in front of goal as Oscar swept the ball into the net with two minutes remaining to spark hope of an undeserved draw.
But as expected it proved too little too late and the holders know they are now under pressure, but they only have themselves to blame.
Shakhtar Donetsk Kucher, Hubschman.
Chelsea Cole, Luiz.
Man of the match Fernandinho. Match rating 7/10.
Possession: Shakhtar Donetsk 54%. Chelsea 46%.
Attempts on target: Shakhtar Donetsk 13. Chelsea 11.
Referee D Skomina (Slvn).
Luiz: it was a shocking performance
David Luiz spoke of his shock after Chelsea capitulated in the Donbass Arena last night. A late Oscar goal gave the final score a distorted slant for Roberto Di Matteo’s men, who were outclassed from start to finish.
“I am shocked by the performance,” said Luiz. “We didn’t play well. It was a shock performance. The second half was a shock again. Congratulations to the Shakhtar players. Sometimes you cannot play well. We need to think of the next game. Chelsea is a big club and we need a win.
“I think that Shakhtar played so intelligently and didn’t give us the opportunity to just win the game. Only in the last 15 minutes did we press.”