The game at Stamford Bridge is not one that either Chelsea or Arsenal cannot afford to lose.
Pressure on both Rafa Benitez and Arsene Wenger for three points
In the home dugout, a Champions League-winning manager, the only one in almost three decades to win two Spanish titles for any club apart from Real Madrid and Barcelona. In the away dugout, the most successful overseas manager in the history of English football.
By any standards, Rafa Benitez and Arsene Wenger have proved extraordinarily effective managers. But a focus on the here and now can obscure a glorious past and after a week in which the pursuit of the world's most coveted coach came to an end, they were interested observers, rather than wanted men.
They convene at Chelsea today in very different positions, yet with certain marked similarities. Theirs are careers at a crossroads.
If one interpretation of Pep Guardiola's decision to spurn Chelsea's advances and sign for Bayern Munich next season was that Benitez had been granted a reprieve, it lasted a matter of hours.
Then came the familiar cascade of boos when Chelsea failed to beat Southampton after they frittered away a two-goal lead to draw.
"He is not necessarily an interim manager," said Wenger, the Arsenal manager. "Maybe he will stay for longer." But few believe that.
Benitez is unwanted by the club's supporters now and, in all probability, by Roman Abramovich in the summer.
Even as the Spaniard said "we have to win together and if we do I'm sure the fans will be happy", the reality is that there are divisions between manager and supporters in a declining season.
Briefly in title contention, Chelsea have tumbled out of it. They have already exited the Champions League and, before the week is up, they could be out of the League Cup, too.
And yet, should they defeat Arsenal today, they will be 11 points ahead of their capital rivals.
"If we win, we will have a big difference," Benitez said.
A derby could have a devastating effect on the Gunners' hopes of securing a 16th successive season of Champions League football.
Wenger's men have been great constants in the competition but the manager's notion that fourth place is like a trophy in itself has come at a time when Chelsea lift actual silverware on an annual basis.
They have changed the context of Wenger's reign. It can be divided into two halves: before and after Abramovich. Or, to be more precise, before Abramovich's money started to tell.
Wenger's third and last league title came in 2004, 12 months after the Russian's takeover but when Arsenal's Invincibles had already been assembled and, in Thierry Henry, they had the finest player in the country. Twelve months later, they were knocked off their perch by the nouveaux riche, masterminded by Jose Mourinho. Wenger won the FA Cup that season, but it was his last major honour.
Much as the Emirates Stadium has been a drain on his resources, the economics graduate knew Arsenal could not afford the cost of keeping up with Chelsea in the transfer market.
The goalposts were shifted by an influx of Russian wealth. So today Wenger encounters a team likely to have a £50 million (Dh291.5m) striker, Fernando Torres, on the bench, potentially alongside one of the £80m trio of creators, Eden Hazard, Juan Mata and Oscar, should Benitez drop the Brazilian.
His finest left-back, Ashley Cole, is in his seventh season as a Chelsea player. Benitez is his eighth manager in that time.
A lack of job security is the price paid for accepting Abramovich's terms of employment.
It is institutionalised short-termism whereas Wenger's longevity is exceeded only by Sir Alex Ferguson's. He is now in his 17th year at the helm but could empathise with Guardiola.
In days gone by, his achievements brought scrambles for his services; Real Madrid and Barcelona were both interested.
Now the assumption tends to be made that he wants to stay at Arsenal. Now, however, the Gunners' struggles mean that a section of supporters do not share that wish.
"He's one of the best, if not the best, manager to manage in England for many years," said Benitez, which may be another dig at Ferguson but is also an indication of Wenger's standing.
Now his doubters disagree, feeling his best days are confined to the past.
Yet their dissent will be nothing compared to the reaction of the Chelsea supporters to Benitez should he should and his side lose again today.
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