Rafa Benitez was disrespectful to Queens Park Rangers when he decided to drop both Juan Mata and Eden Hazard and he has been punished with a result that leaves his approval rating amongst Chelsea fans at an all-time low.
Benitez failed to take Wednesday night's game seriously. Chelsea have an FA Cup game at the weekend and that's when he could have rested his players. Instead he chose a London derby. His team selection was a derogatory act towards QPR and offensive to Chelsea's own fans, who take local pride seriously.
In 27 years Chelsea hadn't lost at home to QPR once, so it's hard to overestimate just how damaging this defeat will have been in the eyes of their supporters.
It was certainly the biggest shock of the season so far: given how Chelsea have been playing of late you could never see it coming. As a former QPR player in particular it came as a huge surprise. We used to beat Chelsea often at home but at Stamford Bridge - no matter who was playing or what respective league positions the two teams were in - we could never win.
So to see a QPR team that has had such a terrible season get a victory away at Chelsea after nearly three decades of waiting was astonishing. This scar will take a long time to heal for the Blues though.
Resting both playmakers was an unnecessary risk. Hazard, maybe, as he has been off the boil, but as soon as Mata's name was left off the team sheet the initiative was handed to the visitors. It left Chelsea looking a rather ordinary team as they started going more direct, and that suited QPR nicely.
Ryan Nelsen and Clint Hill were relishing the chance to get close to Fernando Torres and deal with balls through the centre. Without those inventive players around him, Torres looks very ordinary. There was no movement and no creativity. Benitez made a rod for his own back.
I don't think he realised what a huge game this would be for QPR, especially coming off the back of such a terrible performance against Liverpool which left them humiliated.
Chelsea, by contrast, have had a good run of late and the fans were getting behind the players because they were playing well and winning games. But they were never going to forgive Benitez and now this terrible result has given them an opportunity to target him with renewed criticism.
Benitez will have to redouble his efforts to win them over now. In isolation, losing a game isn't the biggest crime in the world. But losing a game against a QPR side that had won only once all season? It was a disaster.
Let's not sugar-coat it: losing to Queens Park Rangers is a massive setback for Chelsea supporters. They have been turning their noses up at QPR for years, always thinking they are bigger and better. So this is a real kick in the unmentionables for them.
Defeat leaves Chelsea 14 points behind Manchester United and that, I am afraid, is that for their title chances, even if they do have a game in hand. They had a good run but now they need to focus on the top four.
You can't consider them as title contenders. Not with defeats like that.