Chelsea played the last 60 minutes of the fixture with 10 men after Tiemoue Bakayoko’s red card capped a dreadful individual 30-minute performance – in which he gifted Watford four chances. The Hornets – who had won only one of their previous 12 Premier League games – led controversially as Gerard Deulofeu went down easily under keeper Thibaut Courtois’ challenge and Troy Deeney netted the resulting penalty.
Chelsea, then brought on Olivier Giroud for a debut in the second half to add pep to the attack before Eden Hazard, scored an equaliser on the 82nd minute from 25 yards. Two minutes later, Daryl Janmaat scored a fantastic goal of his own when he cut in from the right wing, played a one-two with Roberto Pereyra and beat another couple of defenders before scoring with his weaker left foot.
Deulofeu added another when he ran from halfway before his shot was deflected home by Gary Cahill – and Pereyra scored a fourth from Abdoulaye Doucoure’s through ball.
The Hornets are now six points above the relegation zone.
Gracia, who replaced Marco Silva last month said “It was a great victory and a great match. I am very proud of my players.
“We played a good match, pressed high. The match changed after the sending-off but I think we played very well. Chelsea are a very big club, a big team.”
It was Chelsea’s second consecutive defeat by three goals in the Premier League, following their 3-0 home reverse against Bournemouth.