Sergio Aguero scored a hat-trick as Manchester City moved top of the table and handed Watford their heaviest ever top-flight defeat.
Previously unbeaten Watford could have also topped the Premier League with a win against Pep Guardiola’s side, but they were undone by City’s prolific attack who have now scored 15 goals in three matches.
Aguero headed home a Kevin de Bruyne free-kick before tapping in from close range four minutes later, after brilliant build-up play from Gabriel Jesus and a final pass from David Silva.
Jesus added a third before half-time – his fifth of the season – when he drilled home from Aguero’s cut-back, despite tame calls for offside from the Hornets defence.
Watford had kept three clean sheets this season, and came out reinvigorated after half-time, with Andre Carrillo and Richarlison both having decent chances.
But City continued to push forward and added three more.
Nicolas Otamendi headed in David Silva’s corner before Aguero completed his hat-trick when he poked home after a pulsating solo run into the box.
Raheem Sterling completed the rout from the penalty spot, after he was brought down by Christian Kabasele.
Talks of a hangover from a midweek 4-0 win at Feyenoord in the Champions League were quickly put to bed when Manchester City got started at Vicarage Road.
Guardiola’s side controlled possession throughout, and returned from the half-time break wanting more even after taking a 3-0 first-half lead.
“It was so good. Especially after an away game in the Champions League. The way we played as a team, we are so happy,” said the City boss.
“I was lucky to manage Barcelona with many outstanding performances but this week has been a lot of goals. We have found our game, we can make short passes and we have a lot of energy from our full-backs.”
City had 28 shots in total with 10 on target – five in each half – while individually, David Silva had 88 touches, completing 93% of his passes with two assists, and De Bruyne also impressed making four key passes and setting up the opener.
But Aguero was the one man who impressed the most.
Aguero was in uncompromising form in front of goal once again, and he has now scored nine goals in five games against the Hornets.
Guardiola particularly enjoyed the 29-year-old’s third goal, where he received the ball from Kyle Walker, ran past several yellow shirts and maintained his composure to sneak the ball home from an acute angle.
“His numbers speak for themselves,” said Guardiola. “I’m so happy for the third goal because he’s so clever in the box. He’s able to score a goal at any point.”
Aguero’s hat-trick – his sixth in the Premier League and 10th for City – has moved the Argentine only two away from Manchester City’s all-time scoring record of 177, set by Eric Brook between 1928 and 1940.
Marco Silva had made a good start to life as Watford manager, with two wins and two draws from their opening four league matches.
But City provided the Hornets with their first real test from a title contender and they buckled under the pressure.
Despite being under the cosh for the first half an hour, Watford were able to break forward on the counter-attack and Richarlison had the best chance to head home before City went on the rampage.
Silva felt aggrieved that the offside flag was not raised for Aguero’s opener and Jesus’s goal in the first half, although the decisions were not wildly contested by the players on the field.
They also had a penalty shout when Walker clumsily clattered into Nathaniel Chalobah.
The Hornets did not play badly, but City were just too good.
