The shock must have been even greater than the shame. Chelsea are now suffering from an overload of disbelief. This, after all, was the first away victory of the season for opponents who were swamped 5-1 at Newcastle United a couple of weeks ago. Before anyone dwells on Chelsea's defects and mistakes it should be emphasised that Sunderland performed to a high standard, with a sharpness of passing and movement that distressed the losers.
Chelsea were disadvantaged by the absence of Alex and John Terry, who were, respectively, ruled out by a knee injury and a recurring nerve problem, but that does not amount to an explanation for the sluggish blandness. It felt as if the 28 goals previously amassed in the Premier League must have been the work of an entirely different batch of players.
The plain fact may be that there is less depth to Carlo Ancelotti's means than is supposed. With Ramires yet to make an impression since his £18m move from Benfica, Chelsea cannot avoid seeming depleted when Michael Essien and Frank Lampard are unavailable. Few had envisaged that Sunderland would appear the club of lavish means. They enjoyed excellent contributions from Nedum Onuoha and the devastating Danny Welbeck, who are on loan from Manchester City and Manchester United.
There was a verve and confidence about them and others that was not echoed anywhere in the Chelsea ranks. The closing goal of the afternoon epitomised the difficulty they had even to get within reach of competence. Ashley Cole's attempt to find his goalkeeper Petr Cech in the 87th minute instead invited Welbeck to score his first goal for the club. Once Chelsea get over the ignominy of it all they can start to wonder how they will guard their two-point lead in the table.
There is a jaded air about them and the loss at Liverpool last weekend was followed merely by a trying 1-0 win over Fulham at home. There was to be virtually no reaction once Sunderland assumed an overdue lead. Ancelotti's men's last loss here in the Premier League was a 4-2 beating by Manchester City in February and it is true that Chelsea did not allow themselves to be distracted as they went on to win the title.
It will take real persuasiveness to convince onlookers that such momentum will be re-established. The side is missing people like Terry and Lampard because, to some extent, the defender and the midfielder are hampered by wear and tear. The captain is not quite 30 yet but his body has sustained the degree of damage associated with a veteran. The whole line-up was to be affected by a power cut against Sunderland.
There was also a thought-provoking aspect to the game in the boldness shown by opponents who had two outright attackers and plenty of adventure from midfield. Steve Bruce's plan was pragmatic in its own way since the intention was to apply a stress that would make Chelsea buckle. Others will take note of the manager's scheme and ask themselves whether their squad might be capable of copying it.
The opener felt like a barrage. Cech saved first from Asamoah Gyan, after a cross from Welbeck, before denying Kieran Richardson. Nedum Onuoha, however, maintained the onslaught, going past Mikel John Obi and José Bosingwa before shooting home, with Branislav Ivanovic too late to intervene.
Chelsea had gone 916 minutes at home in the League without losing a goal, but others were inevitable here. Ivanovic, may have been lucky to receive a yellow card from the referee, Chris Foy, rather than a red when hauling down Welbeck five minutes from half-time.
The lead was extended in an entrancing manner in the 52nd minute. Welbeck combined with Jordan Henderson, who may make his England debut on Wednesday, and Gyan, a £13m signing from Rennes in the summer, converted the chance with complete confidence. Such composure was scarcely a surprise from a man who now has four goals from his last three matches.
It was a weekend when Arsenal were the one member of the top four to win. That does reinforce the suspicion of decline amongst the prominent clubs. Arsène Wenger's team are an exception since it will be almost impossible for them not to improve in view of the comparative youth in the line-up. Conversely, a lack of knowhow contributed to League defeats by West Bromwich Albion and Newcastle at the Emirates.
The evidence is, of course, mixed, with all four of England's representatives at the head of their Champions League groups. If the standard of opponent is less high on the domestic front, it may still be because there is a frenzy there that can be debilitating. Chelsea, at least, were weary and despondent long before the close.
This is not a news report and may contain views expressed by the author which are not supported by GNM.