Watford piled more pressure on manager Antonio Conte as Chelsea suffered a 4-1 Premier League loss at Vicarage Road on Monday night.
The defeat comes just five days after a 3-0 home humiliation to Bournemouth which saw the Blues boss face increased questions about his job security.
And their failure to collect all three points at Vicarage Road will see calls for his sacking increase following another listless performance by the defending league champions.
Chelsea were poor from the start, and were reduced to 10 men after just a half an hour, when the calamitous Tiemoue Bakayoko received a second yellow card for a clumsy challenge on Richarlison after giving possession away in the middle of the pitch.
Watford pounced on the man advantage.
And it was ever-present new signing Gerard Deulofeu who set up the opportunity in the 41st minute.
The Barcelona loanee beat Chelsea goalkeeper Thibaut Courtois to a through ball in the box, touching the ball away just before the outstretched Belgium international took him down.
Troy Deeney converted the ensuing penalty to give Javi Gracia’s side a much-deserved lead – his powerful shot from 12 yards leaving Courtois rooted to his spot.
Conte was the first out of the changing room to start the second half.
But his team found it difficult to muster the necessary response early on as the hosts continued their strong display with the man advantage.
New signing Olivier Giroud made his debut on 63 minutes in hopes of providing a spark from the bench – something he made a habit of at Arsenal.
But it wasn’t until the 81st minute when Cesc Fabregas dragged an effort straight at Orestis Karnezis that Chelsea looked dangerous.
But his shot jolted the game to life and Eden Hazard evened the match just seconds later with a wonderful effort that left Karnezis no chance – the Belgium international curling a shot from 20 yards around the keeper and into the side netting.
Deulofeu dinked an effort wide of the post in the 84th after being played in by a through ball.
And Watford secured the three points moments later with a well-worked one-to-one from which Daryl Janmaat slid his shot past a helpless Courtois from inside the box.
The excellent Deulofeu then scored a deserved goal two minutes from time and Roberto Pereyra added a fourth to give the Vicarage Road faithful a memorable night against Conte’s side.