Super sub Joe Cole came to the rescue of Chelsea as the big-spending Stamford Bridge side pulled off a smash and grab raid that left Birmingham City reeling at St Andrew's.
Cole's introduction as a 63rd minute substitute finally sparked Chelsea into life and it was one of the trademark runs of the England international midfielder that led to Chelsea securing their hard earned win.
His 69th minute shot was deflected home by the Birmingham central defender Martin Taylor as Chelsea maintained their 100 per cent start to the season.
But the defeat was rough on Birmingham who had dominated the match for long spells.
Birmingham's manager Steve Bruce pulled off a tactical masterstroke when he opted to play with five midfielders and a lone striker - Emile Heskey.
It caught out Chelsea and Jose Mourinho's side struggled to get to grips with the system.
Birmingham could easily have been out of sight before Cole's lucky goal but a combination of some poor finishing and the Chelsea goalkeeper Petr Cech frustrated them.
Birmingham were clearly intent on hustling Chelsea out of their stride from the opening whistle and it was a tactic that paid off.
Chelsea could not cope with Birmingham's all action style, that was personified by the non-stop effort of Robbie Savage in midfield, and they were extremely unfortunate not to have opened up a comfortable lead by half-time.
As early as the third minute, Chelsea were left riding their luck to stay on level terms when Julian Gray fired wide from close range after Damien Johnson saw his shot blocked.
But, despite the fact that they spent most of the opening period on the defensive, the best chance of the first half did fall to Chelsea.
It was handed to them on a plate in the 13th minute after a mistake by Birmingham's former Chelsea right-back Mario Melchiot who moved to St Andrew's from Stamford Bridge earlier this summer.
Melchiot's attempt at a clearance only found its way into the path of Didier Drogba who was faced with just Maik Taylor to beat from six yards. But somehow Drogba pushed his shot wide.
It was a rare moment of menace from a Chelsea side who struggled to create any more openings in the first half, due in no small part to the fact that Savage carried out an effective man to man marking job on Frank Lampard.
Birmingham looked far more dangerous and only some poor finishing and the heroics of Cech kept Chelsea on level terms at half-time.
Cech came to Chelsea's rescue twice in the space of five minutes.
First he beat away a drive by Heskey from eight yards after he had intercepted a misplaced back pass by Wayne Bridge.
The Cech had to be alert to push a free-kick from Savage over the bar.
Heskey then headed wide in the 28th minute before Chelsea had a double let off in the space of five seconds at the end of the half.
Muzzy Izzet's snap shot was deflected into the path of Gray who managed to beat Cech from close range only to see his shot bounce off the post.
The rebound fell straight to Gray but this time he sliced his shot over the bar with Cech beaten.
Mourinho reacted to his side's lacklustre first-half display by hauling off Eidur Gudjohnsen and Alexei Smertin and replacing them with Mateja Kezman and Tiago.
But Birmingham began the second-half as they had started the first - in control and on the front foot.
Melchiot flashed a 48th minute header over the bar before Chelsea were finally given some respite when Geremi found himself unmarked in the Birmingham area with just Taylor in front of him.
But Taylor proved to be as resilient as Cech when he threw out his right-hand to turn away Geremi's shot.
Mourinho made his third and final change when he replaced Geremi with Cole in the 63rd minute.
He was banking on the running of the England international to unlock the Birmingham defence and his introduction paid an almost immediate dividend as Chelsea stunned Birmingham to take a 69th minute lead.
Cole cut in from the left wing and fired in a low drive that Taylor seemed to have covered.
But the shot took a wicked deflection off Drogba and flew into the bottom corner of the net with Taylor left flat-footed.