Television pictures clearly showed a frustrated Wilshere make a one-fingered gesture during the second half of a disastrous game for the Premier League leaders, who now lead City by only three points.

There was also an angry exchange between team-mates Per Mertesacker and Mesut Ozil as they left the field, although Arsenal manager Arsene Wenger laughed off that confrontation.

"That's the Germans!" joked Wenger. "They will sort that out between themselves, don't worry about it."

However, the FA are likely to look upon Wilshere's behaviour with less humour and, even if referee Martin Atkinson fails to mention the incident in his report, the ruling body has the power to charge the England international with improper conduct.

Liverpool's Luis Suarez served a one-match suspension for a similar offence two seasons ago.

"I didn't see that," said Wenger of Wilshere's actions. "I don't know if he did it. If he did it and he's banned, we will have to accept it."

Surprisingly, given that City have now scored 31 times in their last six home games and also scored six against Tottenham Hotspur, as well as four against Manchester United, Wenger refused to accept that Manuel Pellegrini's side are Arsenal's primary rivals for the title.

"I don't know. We will see," said Wenger when asked if the defeat was significant.

"They are one of the teams to beat, but not more than any other team. We have played against Everton, who are as good as City; we have played against Southampton, who are as good as City.

"What hurts me more is we had the opportunity to put City at nine points (behind) and they are three tonight (Saturday). That's very difficult to swallow because that was a team that was not unbeatable today."

Wenger's claims rang hollow, however, given City's degree of dominance, with Pellegrini enjoying goals from Sergio Aguero, Alvaro Negredo and David Silva, a Yaya Toure penalty and two from the impressive Brazilian Fernandinho.

Wenger, who claimed his side were denied a clear penalty and were on the receiving end of three incorrect offside calls, saw his team score through a Theo Walcott brace and a late Mertesacker header.

For Pellegrini, the victory followed hot on the heels of an impressive Champions League success at Bayern Munich; a result slightly overshadowed by the manager's confession that he did not realise how many goals his team needed to score during that game to top the qualifying group.

"This was a more complete game than against Bayern Munich because we couldn't score four against Bayern and there were a lot of complaints about that," joked the City manager.

"But I don't think that was our best performance, because Arsenal scored three goals and that's too many for the chances they had.

"But it was a very complete game in an attacking sense, because it is not easy to score six goals against Arsenal. They have the best defence in the Premier League, and we had at least four or five more clear chances to score."

The display of Fernandinho, signed for �30 million ($49 million, 36 million euros) from Shakhtar Donetsk in June, was a particular high point for Pellegrini, who said: "Fernandinho played the perfect game.

"Not only did he score two goals, but he played very, very well, recovered a lot of balls during the whole game and showed great pace. I'm very happy for him, he is a top player and you will see every game how he will continue to improve."

Only a calf injury suffered by Aguero could take the gloss off another scintillating City display, with Pellegrini awaiting the result of medical tests.