If Antonio Conte was under any illusions as to the gentle fragility of his side of battlers, then that should no longer be the case after this trip to The Liberty.
130 seconds is all it took, to turn from comfortable ascendency to embarrassed also-rans; and though they eventually battled back to parity, this was clearly two points dropped rather than one rescued.
Opening a match to the sound of a danced-up version of The Dying Swan, from Tchaikovski's Swan Lake, might be considered an odd way to rouse the home side.
Though one local wag joked it was completely appropriate, given some recent performances from Francesco Guidolin's XI.
Chelsea started in combative style, though it was their hosts who had their troops fighting dirty: Jordi Amat could easily have seen several yellows for a series of early challenges on Diego Costa.
The striker's opening goal was fair reward for a period of domination: though one most characterised by a failure to take the chances that presented themselves.
The first period continued in much the same fashion, and Chelsea should really have been home and dry by the time the half time bara brith was being served-up in the press room downstairs.
The second period was more see-saw in its balance, and it could be seen that far from romping home here, Chelsea's biggest test would be to extend their lead, before Swansea grabbed the chance to equalise.
They failed in that task.
Thibaut Courtois had a recent change in the rules to thank for the fact he was not again seeing red against this opposition – as he did in the opening game of last season at Stamford Bridge.
Having at least attempted to take the ball from Gylfi Sigurdsson, and with the Icelander being pushed out away from goal, referee Andre Mariner made the call right – pointing to the spot, and letting the Belgian off with a caution.
Sigurdsson equalised, but parity was not to last for long.
The credit Marriner had earned in his penalty call was all but lost inside two minutes, when he missed a clear foul on Gary Cahill beyond the edge of Chelsea's box.
The expectation here, had the rules been followed, is that the game would have been halted: free kick to Blues.
But the greater error in the moment was by Cahill who, in relying on that to happen, forgot his basic Day One training: in not putting the ball into Row Z of the stands.
You play to the whistle, and in failing to do so, Cahill must ultimately carry more of the can for the goal that followed from Leroy Fer than any error-prone official.
And, so, Chelsea looked set for their first defeat under Conte.
The minutes that followed were a frustration: Conte clearly wants his side to play a passing game, and he also clearly knows they are a fair way short of proficiency in that department just yet.
But his desire to stick to that plan, at the expense of potentially game-changing substitutions, is already starting to frustrate.
He has had to divert from Plan A to win the majority of Chelsea's points this season, through he seemed reluctant to do that here until the very last moment possible.
Cesc Fabregas has been Conte's Plan B, but here that was left until the 76th minute – replacing Nemanja Matic, who had been coasting for some time by this stage.
Victor Moses, on for Willian a minute later, was another tried and tested switch.
And the goal did follow – a moment of brilliance from Costa who bicycle kicked it acrobatically past Lukasz Fabianski, who had pulled off a series of fine saves up to that point.
That Michy Bashuayi, to many the obvious answer to the questions posed on pitch, was not introduced until two minutes before the added time board was held aloft, was a matter that only caused yet more annoyance to those watching the drama.
Chelsea remain unbeaten, but this still looks like a manager who is getting to grips with how to make his team work the way he wants.
Defensively, in particular, there are issues: and a late, late injury to John Terry, which saw him hobble out of the stadium on crutches, will cause a real selection headache for Friday's visit of Liverpool to west London.
With error-prone bodies in both central defence and goal, is David Luiz really the answer to shore things up at the back?
Blues first big test of this new era is about to present itself.