The Blues boss made the trip to Vicarage Road with his ongoing presence at Stamford Bridge already being called into question .
A 3-0 defeat to Bournemouth on home soil had seen uncomfortable questions asked of the Italian amid reports of dressing room unrest.
Conte would have been hoping for a positive response against Watford, but he got another abject display.
Chelsea’s cause was delivered a damaging blow inside half-an-hour when Tiemoue Bakayoko was sent off.
There was brief hope when Eden Hazard cancelled out Troy Deeney’s penalty eight minutes from time, but a late collapse saw the visitors leave with their tail between their legs .
Not since 1995 have the Blues suffered such crushing defeats in back-to-back top-flight fixtures, with the wheels having fallen off in some style for the reigning champions.
3 - Chelsea have lost consecutive Premier League games by a margin of 3+ goals for the first time since October 1995 (1-4 vs Man Utd and 0-3 vs Blackburn). Humbled.— OptaJoe (@OptaJoe) February 5, 2018
Ill-discipline has been a problem for Chelsea this season, with Bakayoko the latest to have seen red in a campaign of far too many cards.
7 - Only Grimsby Town (8) have been shown more red cards in all competitions of English football this season than Chelsea (7). Rash. #WATCHE— OptaJoe (@OptaJoe) February 5, 2018
While the Blues now face another testing period of reflection, with Conte’s position under serious threat, Watford can bask in the claiming of a prized scalp.
The Hornets do not have the best of records against Chelsea, but they are now revelling in a first victory over the west London giants in 14 attempts — with that sequence stretching back to a 1-0 win in September 1999.