Manchester City's flying start in their 8-0 demolition of Watford was "weird" and "not normal", according to Pep Guardiola.

The City boss watched his side career into a 5-0 lead inside 18 minutes – the quickest such an advantage has been established in Premier League history – courtesy of goals from David Silva, Sergio Aguero, Riyad Mahrez, Bernardo Silva and Nicolas Otamendi.

Bernardo Silva went on to complete a hat-trick after half-time and Kevin De Bruyne, who orchestrated so much of the champions' best work, completed the scoring to give City their biggest ever top-flight win on the weekend the club celebrated their 125th anniversary.

Guardiola reflected on a very different outcome to last weekend's 3-2 loss at Norwich City, but acknowledged two early chances that fell to Watford forward Gerard Deulofeu could have altered the complexion of the contest.

"It is weird, it is not normal," Guardiola said. "Five shots, five goals. In the same time, we gave them two chances to score.

"The quality we have is a joy to watch. After 5-0 the game is completely different. We were ruthless in terms of five shots, five goals.

"Sometimes you shoot 15 times or 20 and can’t do it. It was a lovely day for all of us, for our City fans in the sunshine and a lot of goals."

Guardiola was impressed by the continued application of his players throughout the contest and rejected the suggestion City trying to score goals throughout showed a lack of respect to beleaguered opponents, who they hammered 6-0 in last season's FA Cup final.

"The best way to humiliate the players is to do stupid things in the second half, make some fashion movements [showboating]," he said.

"We play for the spectators, who come here to watch the game. I would not like to see my team in the second half not run much because we are winning 5-0.

"That is a lack of respect for our opponents."

Benjamin Mendy was withdrawn at half-time on his first start since April, but Guardiola reported no adverse reaction for the France left-back, who has endured a lengthy battle back to fitness following a second bout of knee surgery in as many years.

"He is well. After two years without playing, 45 minutes was enough," Guardiola said.

"Angelino [who made his Premier League debut as Mendy's replacement] is incredible. He deserves to play after 5-0. I am glad. I saw many good things."