Runaway leaders Manchester City showed no ill-effects from the end of their 18-game Premier League winning run by comfortably beating Watford.
Playing two days after the 0-0 draw at Crystal Palace, City took just just 38 seconds to open the scoring as Raheem Sterling slotted home Leroy Sane's cross for the quickest goal in the Premier League this season.
City, who are 15 points above second-placed Manchester United, doubled their lead when Kevin de Bruyne's cross was turned into his own net by a sliding Christian Kabasele.
De Bruyne, who started the match after recovering quickly from a nasty looking injury against Palace, then had a free-kick tipped on to the bar by Heurelho Gomes.
City got the third goal their dominance merited when Sergio Aguero scored from close range after the Watford goalkeeper parried De Bruyne's cross.
Andre Gray netted a late consolation for Watford, tapping home Andre Carrillo's low cross.
The visitors, who remain 10th by virtue of their early season form, have lost 10 of their past 14 games.
De Bruyne recovered immediately from his Palace knock to start, while defender John Stones returned from the hamstring injury which had sidelined him for over a month and playmaker David Silva was back after two games out for personal reasons.
However, Guardiola said after the game that Silva might need more time off.
City - wanting to make things right after dropping points for only the second time this season - led 2-0 after 13 minutes. They could almost relax at that stage against a team totally out of form.
Sterling's opener was City's third quickest in the Premier League era.
Aguero - who has now scored 10 goals in six games against Watford - would have scored earlier had Kabasele not turned De Bruyne's cross into his own net before it reached the Argentine.
He missed a hat-trick of chances from De Bruyne crosses, denied twice by Gomes and heading well wide, before scoring after the goalkeeper's fumble.
Stones also fired a glorious chance well over from six yards, and headed straight at Gomes from the rebound after De Bruyne's free-kick was saved onto the bar.
Watford's late goal denied them a perfect day, with a run of three consecutive clean sheets coming to an end.
But they are now 16 games away from an unbeaten Premier League season, despite Guardiola's insistence it will not happen.
The one concern was right-back Kyle Walker walking off holding his groin at the final whistle, and Guardiola said the club would have to "check it out".
Watford's decline this season coincided with Everton sacking Ronald Koeman. The Toffees wanted Marco Silva to succeed the Dutchman, but the Hornets refused to let him go.
And since Koeman's departure, Watford have only taken 10 points from 13 games.
A visit to Manchester City was probably not one they would have expected to get something from, but they were basically out of the game within 38 seconds.
Watford had only touched the ball once - when Richarlison was tackled by Silva - by the time Sterling tapped home.
They were well beaten by the time Gray, who earlier forced a save from Ederson, was able to turn home Carrillo's cross.
They did rally after the goal, but even the most optimistic Watford fans would have known it was a consolation and not the start of a comeback.
Watford boss Marco Silva: "We did everything in a different way to how we prepared. We were too soft in the first 20 minutes.
"Too much respect and some nerves. I told them to compete here. The first thing we need to do is not be scared or nervous.
"We had chances. The last 20 minutes we were better. We need to compete for the whole 90 minutes.
"Congratulations to Manchester City, what they are doing is amazing. Pep Guardiola is showing he can do his philosophy in the Premier League."
Manchester City manager Pep Guardiola: "[The Palace game] was the first time we dropped points in 19 games and you saw the reaction in the first 15 minutes.
"In the second half when we could have been more tired and complacent thinking about the result, we were completely the opposite. We played an amazing performance and we scored another goal and we could have scored more.
"Our fans were a little bit quiet because maybe they were freezing and maybe because it is our fans and the way we express our happiness but I think our team showed a lot of good things today so it means a lot for us."
Neither side are in Premier League action for a week and a half.
Manchester City host Burnley on Saturday (15:00 GMT) in the FA Cup third round and are then at home to Bristol City in the Carabao Cup next Tuesday (19:45 GMT).
Watford face Bristol City next - in the FA Cup on Saturday.