Chelsea's renewed motivation in the 2-2 draw with Spurs should be seen as nothing but a savage indictment of their attitude this season.
Guus Hiddink will have been delighted with the passion, energy, and intensity his players showed in the second half, but he - and quite possibly, Jose Mourinho - will be asking why they have not been doing that all season.
As defending champions, Chelsea were favourites for the title, which was, of course, won by Leicester City. Instead, they are set for a mid-table finish after a woeful start to the campaign, and while they have improved under Hiddink, it has not been enough to even mount a challenge for Europe.
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Questions to be asked
Even in December, when Mourinho was still in charge, it could be accepted that this was not to be Chelsea's season. The Portuguese boss appeared to have lost the dressing room, and something was not quite right on the pitch.
Frustratingly, they have not been able to rediscover what it was that made them champions in the first place. Until Monday night, that is, when the severity of the situation became clear - Tottenham could have been about to win the Premier League instead.
It is understandable that Chelsea wanted to raise their game even more than they usually would for a London derby. But this was a game that could be clearly divided into two halves.
The first, Spurs cruised into a 2-0 lead thanks to goals from Harry Kane and Heung Min-Son. The second, Chelsea came alive. Spurs can be accused of precisely the opposite, and they too must learn from the manner in which they fell apart at Stamford Bridge.
Spurs' discipline disintegrated entirely, but the home side's taunts made it clear that this was a game that meant far more than earning another three points to climb up the table.
Eden Hazard is particularly guilty. He spent the week leading up to the game warning Spurs that he would not allow them to win the league, and miraculously appeared from the bench to score an excellent goal for Chelsea's equaliser. A shadow of his former self, the dynamic superstar who scored the goal that won the league last season, he appeared more delighted to have won it for someone else this time around.
Chelsea have a wider issue to deal with. It is not just that they have been underperforming, but they should be suitably alarmed that only a sense of schadenfreude at Tottenham's expense was able to rouse them from their season-long slumber.
What has been Chelsea's main problem this season? Have your say in the comments.