City led in the first minute when David Silva was set up by Kevin De Bruyne, with the champions maintaining their frantic early scoring pace to go up 5-0 inside 18 minutes.
That in itself was a Premier League record, but City could not quite manage to equal the competition’s biggest ever win, Manchester United’s 9-0 defeat of Ipswich Town in 1995.
Bernardo Silva hit a hat-trick as City impressively bounced back from a shocking loss at the hands of injury-hit Norwich City last time out in league action.
The emphatic result boosts their goal difference to +18 and moves Man City within two points of leaders Liverpool, which is at Chelsea on Sunday.
As for bottom club Watford – who replaced Javi Gracia with Quique Sanchez Flores earlier this month – they will have to reflect on their heaviest defeat in league competition.
City also humiliated Watford in last season’s FA Cup final, running out 6-0 winners with Gabriel Jesus and Raheem Sterling each scoring a brace at Wembley.
