Chelsea have in seasons past either been the team gunning for glory or able to play party-pooper. Not tonight.

A dismal 5-0 defeat at the Emirates Stadium has put pressure back on Mauricio Pochettino, with hopes of qualifying for Europe again far from certain.

There were concerns before kick-off when academy star Alfie Gilchrist and an out-of-sorts Benoit Badiashile started. With less than four minutes of the clock, Leandro Trossard has exploited Gilchrist’s naivety to open the scoring.

Gilchrist and Marc Cucurella were exposed from the off, with wingers Mykhailo Mudryk and Noni Madueke offering little protection in the face of constant stream of attacks. Neither will ever make it at this level if they do not add to their attacking talents.

Ben White scrambled in a finish after a corner as Badiashile and Axel Disasi struggled to command their area and looked overworked.

Chelsea’s midfield was also bullied by physical duo Declan Rice and Thomas Partey, a clear ploy from Mikel Arteta to exploit the softness at the heart of this expensively built team.

The midfield trio of Enzo Fernandez, Conor Gallagher and Moises Caicedo were nonexistent as Kai Havertz added a third after a long Martin Odegaard ball.

Enzo was the worst of the trio, substituted after 66 minutes having barely laid a finger on his midfield opponents, along with the tactically poor Mudryk.

Havertz added a fourth amid yet more poor defending from Cucurella and Badiashile while White’s cross found the net as Arsenal toyed with their London rivals.

It leaves Chelsea 30 points behind Arsenal’s top-of-the-table team in ninth, having taken a significant hit to their goal difference.

If there’s one aspect of Chelsea’s play Mauricio Pochettino can be particularly blamed for, it is not being able to build solid defensive unit.

This is Chelsea's worst defensive season in the Premier League era. They have shipped a club-record 57 goals and still have six games left to play.

It felt like Chelsea were making progress after two back-to-back positive displays against Everton and Manchester City.

But it is always one step forward, one step back. It doesn’t get any easier for Chelsea with a trip to Aston Villa on Saturday and Tottenham coming to Stamford Bridge shortly after.

This is a club so used to dominating London but they look miles off their city rivals. All they could do was give Arsenal the confidence-boosting rout they dreamed of.