Manchester City boss Pep Guardiola says he is not going to ‘waste energy’ on the EFL Cup even though no manager has been more successful than him in the competition.

City edged into the last 16 of this season’s edition thanks to first-half goals from Jeremy Doku and Matheus Nunes, his first for the club, in a 2-1 win against Championship side Watford.

Only Doku and Kyle Walker kept their starting places for a game that began less than 50 hours after the enthralling 2-2 Premier League draw with Arsenal had ended.

With a league game at Newcastle on Saturday lunchtime (12:30 BST), and a Wednesday tie ruled out on police grounds as Manchester United are playing at home to FC Twente in the Europa League, Guardiola opted for a quick turnaround from Sunday rather than the alternatives of switching the game to Watford or playing on Thursday.

“The next round, I announce you, I play the second team,” said Guardiola. “We are not going to waste energy, for sure.”

The fourth round is scheduled for either 29 or 30 October. Although there are no clashes with European fixtures in that week, Chelsea are due to play in the Uefa Conference League when the quarter-finals are scheduled in the midweek before Christmas.

Guardiola is level with Brian Clough and Sir Alex Ferguson with four triumphs in this competition. However, with additional European matches from this season, he feels he has to look at the tournament differently.

“The schedule is the schedule, we cannot handle it anyway,” he said. “Today for [James] McAtee, Matheus [Nunes], Jack [Grealish], Phil [Foden], who didn't play, the young lad, 16 years old, it's perfect,” he said. “That's why it's a good competition, otherwise we wouldn’t win four in a row.

“We play to go through. We never throw a competition. Never. But we played 50 hours ago. I’m not going to [take] a risk with the Premier League and the Champions League in this competition.”

Nunes makes his mark

On a night when 16-year-old Kaden Braithwaite became the third-youngest player to start a game for City, Nunes also had a night to remember, following up Doku's fifth-minute opener with a precise first-half finish.

A £53m signing from Wolves just over a year ago, Nunes has not made the impact envisaged.

The Portugal international started only seven times last season and so far this term has been limited to just 20 minutes' Premier League action across three substitute appearances.

But Guardiola has not discarded Nunes in the same way he exiled another expensive midfield purchase, Kalvin Phillips, and two days after the draw with Arsenal he stepped into the breach with an eye-catching display.

"He has a special quality that few players have," said Guardiola. "He is excellent in space and in the transitions. I am really pleased for him. He's a lovely guy."

Doku had earlier profited from Ryan Porteous' poor early backpass that allowed McAtee to steal possession away from keeper Jonathan Bond. As the ball was recycled to the edge of the area, the Belgian applied the finish.

It helped condemn Watford to a 16th successive defeat against City, although given they had conceded 26 times in their past five losses alone, this could be regarded as a moral victory for Tom Cleverley's side.

Braithwaite, 16, becomes Guardiola's youngest City starter

It is amazing to think Braithwaite was not even six months old when Sheikh Mansour bought City and changed the course of English football history.

From a personal perspective, more startling was that Braithwaite had not trained with City's all-conquering first team until Monday as Guardiola tried to work out which of his senior players should be involved in a game that started so soon after the Arsenal game.

Braithwaite would have been relieved that referee David Webb ruled out a Watford equaliser when Kwadwo Baah barged him off the ball before drilling a low shot home from an acute angle, although the decision was the right one.

The youngster did not look out of his depth, which was another positive given less than a week ago he was turning out at the mini stadium over the road in a Uefa Youth League defeat by Inter Milan.

Another youngster, Nico O'Reilly, was tidy in the central midfield berth, which is encouraging given the expectation Guardiola will be without key man Rodri for an extended period and will be unable to do anything about it until January at the earliest.

Education for Cleverley

For Cleverley, it will have been an education observing Guardiola at such close quarters.

Taking charge of his 18th game as Watford manager, the former England and Manchester United man has outlasted some recent appointments at Vicarage Road - including Claudio Ranieri - and is level with Roy Hodgson.

And while this was his side's third defeat in four games in all competitions, Cleverley has clearly developed a well-organised team.

They did not allow their heads to drop after the early setback and had what their manager felt was a perfectly good equaliser disallowed when Baah was ruled to have shoved Braithwaite over before he converted the chance.

Tom Ince gave them hope of taking the game to penalties with an excellent 86th-minute effort, but in the end it was no more than a consolation.