The money men at Capital One who chose to plough millions into sponsoring this competition presumably never saw this coming, even if they could still end up with something remarkable at Wembley next month. Swansea stand on the brink of a first major cup final after registering a victory here that had Chelsea's players wheezing in disbelief and their support in uproar, with the prospect of a showpiece against Bradford City of League Two very real. There is romance, if perhaps not ratings, to be had in that.
The last time those sides met was in front of 7,347 people at Valley Parade almost six years ago, a game that was drawn 2-2 with a more youthful Leon Britton presumably scuttling effectively at the heart of the visitors' midfield. Considerably more spectators would grace the national stadium on 24 February to see Michael Laudrup's slick side dazzle, even in a final no one would have considered conceivable a few months ago. They may have been on the verge of extinction 11 years ago but they have won at Anfield and the Emirates already this term. Laudrup described those as "historic results" with this, victory over the fading European champions, another swelling the list.
This was a different kind of win, one achieved while chasing the ball for long periods where usually they hog it so stylishly. The home side could cry foul at a harshly disallowed goal in stoppage time or, as Rafael Benítez did, point to profligacy at one end and uncharacteristic sloppiness at the other which condemned them to a first-leg deficit they will do well to recover. Yet with Chelsea so unpredictable at present, Swansea were everything the hosts were not: resilient and ruthless. This tie is surely theirs. "We're still far away," said Laudrup. "We will need a great, great performance, like this one, in the second match because there's still so much offensive potential in Chelsea. But we have a realistic possibility."
He will have enjoyed the journey home on the team bus to south Wales, basking in this success even with a trip to Everton looming large at the weekend. Swansea's attacking football had caught the imagination over their rise through the divisions, but they have successfully allied all that pizzazz with solidity. They were stingy in the Championship, and hardly porous last term when restored to the top flight, with this a lesson in stubborn defence. Ashley Williams was inspirational at the heart of their back-line, the second-choice goalkeeper Gerhard Tremmel excelling to deny Branislav Ivanovic and David Luiz when clear chances were eked out. Those in midfield were industrious throughout, with the bite provided up front by a strike force that cost a combined £5.5m.
They needed that team prowess to prevail. Chelsea had dominated, their own flow summed up by one glorious passing combination delivered at pace by Juan Mata, David Luiz, Oscar, Eden Hazard and Ramires early on with the last Brazilian eventually drawing a save from Tremmel. Yet, with Fernando Torres peripheral on his 100th Chelsea appearance and Demba Ba kicking his heels on the bench until nine minutes from time, they rarely threatened a finish to all the finesse.
Ba, eventually summoned with Frank Lampard, did convert neatly as full-time approached only for an assistant referee, wrongly, to rule him offside. Yet the reality was that, whenever frustration had built, Chelsea imploded at the other end with Ivanovic, usually so dependable, twice culpable of aberrations. The Serb first dawdled as he collected Ross Turnbull's roll out, with Jonathan de Guzmán robbing him of the ball and squaring for Michu to belt in a 16th of a productive campaign from 20 yards. To think the Spaniard cost only £2m is still unfathomable.
Late on it was Ivanovic again who played a blind back-pass towards his goalkeeper which the substitute Danny Graham intercepted, the forward taking his time to convert into the gaping net as both Chelsea centre-halves dived in. Ivanovic marched from the turf at the final whistle staring steadfastly at the ground as all around the implications of this defeat rumbled. This club is mutinous at present, with the rancour likely to be sustained to the summer.
Benítez denied it in the aftermath, but the atmosphere – forever teetering on open revolt – cannot be helping nervous players for all that the locals feel justified in their fury. This game was played out to bellowed chants of disgust from the stands, with calls for the introduction of Lampard and Ba, or the reinstallation of Roberto Di Matteo or José Mourinho, interspersed with hostility at Benítez, the misfiring Torres and even the chairman, Bruce Buck, upon his appearance on the pitch prior to kick-off. There is discord all around and, when that early dominance in possession petered out after the interval, the exasperation duly boiled over.
Other sides might not have had the nous to take advantage but Swansea are too good not to capitalise on such opportunities. There have been Welsh Cups and Football League trophies over the years. This time around, there might be something even more glittering for this club to celebrate. "Aston Villa and Chelsea are still the favourites to reach Wembley," added Laudrup, though momentum is with the underdogs.