First and second in the Premier League, yet to drop a point, and the architects of a day of ritual humiliation for north London by an aggregate scoreline of 13-3. There is added vigour to the Manchester swagger.

City produced the day's first statement of intent with an emphatic 5-1 win at Tottenham Hotspur where Edin Dzeko, so often maligned last season, scored four times for the richest club on the planet. United responded to their local rivals' declaration as they often do, putting them in the shade and Arsène Wenger under further scrutiny with an remarkable 8-2 rout of Arsenal. It was Arsenal's heaviest defeat since 1896, when Loughborough Town inflicted a record 8-0 loss, United's biggest victory since an 8-1 win at Nottingham Forest in 1999 and their greatest at Old Trafford since routing Ipswich Town 9-0 in 1995. It was a result that raised the question to Wenger of whether he would consider his position at the club after 15 years.

"No, because I feel it was under very special circumstances," the Arsenal manager replied, pointing out that eight senior players were absent through injury or suspension and that three games into a new season, one that has brought Champions League football to the Emirates Stadium, is an indecent time for such a debate.

"It is a terribly painful defeat but I don't compare whether it is the most painful of all.It is painful and that's it. We have played three league games and two Champions League games and it is at the end of a season when you can make a balanced decision. Of course this hurts, it was humiliating, but you could see we had not recovered physically from Wednesday night [when Arsenal beat Udinese], we had eight players out, they had class and they punished us."

Arsenal finished without a full complement of players for the third league game in succession, the raw right-back Carl Jenkinson dismissed for a second bookable offence in the 77th minute, and Sir Alex Ferguson was almost patronising in his sympathy. The United manager said: "We scored some fantastic goals. We could have scored more but you don't want to score more against a weakened team like that."

Wayne Rooney scored the sixth hat‑trick of his United career to take his total for the club to 152 goals, beyond Paul Scholes and Ruud van Nistelrooy. "A lot of my milestones have come against Arsenal," said the England striker. "My first ever goal for Everton was against them, so was my first Premier League goal for Manchester United and now the 150th has come against them. It is still very early in the season but it was an incredible performance from us."

Wenger claimed "it was not an 8-2 game" and insisted he is not entirely culpable for Arsenal's struggles in the transfer market. "We have the money if we can find players who can strengthen our team but I am not the only one working on that at Arsenal. We have 20 people working on that, but today we had too many players missing. We didn't have the squad to cope. We have not found the solutions. It is difficult to find excuses after a game like that but we are behind the other clubs in terms of wages."

The Arsenal manager confirmed he is close to signing the Monaco forward Park Chu-Young and denied reports he is interested in the Evertonmidfielder Mikel Arteta. As for increased criticism of his handling of the club, Wenger said: "I am in a public job and I have to accept that. The players we have sold are players I brought to the club. You know me well and should give me more time before saying, 'Have I have got it right?' We were poor defensively and we collapsed more physically than mentally."

Samir Nasri made an impressive debut in City's win and believes the two Manchester clubs have set an early standard. "I had a good game but the most important thing is we won 5-1 and sent out a signal to other clubs," he said. "This is just the start of the season, it's important to keep our confidence, but I'm convinced we have a great team here and can win things," he said.