Roberto Mancini plays down tunnel row after City are halted at Bridge

Mancini was happy to see Chelsea so delighted (GETTY IMAGES)

Roberto Mancini last night welcomed the exuberant celebrations with which Chelsea greeted their 2-1 victory over Manchester City as a sign of his club's arrival as the Premier League's biggest scalp, despite his hosts' glee – and especially that of Ashley Cole – prompting a mêlée in the Stamford Bridge tunnel after the final whistle. The Italian, instead, chose to reserve his scorn for referee Mark Clattenburg, suggesting someone "outside the stadium" could have seen the first-half penalty on David Silva that the official missed.

"I had a friend outside the stadium who could see it was a penalty," the City manager said, after his side's first defeat of the season. "But the referee did not see it. How did he miss it? Because it was raining a lot, maybe."

Mancini identified that moment – rather than the second half dismissal of Gaël Clichy, for two bookable offences – as the instance which changed the course of the game. Television replays suggested Jose Bosingwa caught Silva inside the area, and just two metres in front of Clattenburg, with City still dominant after Mario Balotelli's second-minute opener.

Clattenburg, though, did not award the penalty – though he also failed to book the Spanish international for diving – and by half-time Chelsea were level, through Raul Meireles's first Premier League goal for the club. Frank Lampard secured a third victory inside a week for Andre Villas-Boas's side with an 83rd-minute spot-kick after Joleon Lescott blocked Daniel Sturridge's shot with his arm, a decision Mancini did not dispute.

The Italian denied all knowledge of the subsequent fracas in the tunnel – "I don't know if Cole said something, I don't know what he said" – but it is believed a number of players and technical staff from both sides became embroiled in an argument as Mancini berated the officials over their decision-making. The two sides were separated by stewards and shepherded into their respective dressing rooms after a confrontation lasting around a minute.

Mancini moved to downplay the incident, insisting Chelsea's delight at beating City simply proved his side remain the League's team to beat, despite seeing their lead over Manchester United cut to two points.

"They were really lively because they beat a top team," he said. "It's normal. If the Chelsea players are saying we are a top team, it is important. It is not often a team comes here and plays like we did in the first half. We have lost one game, but it is a very long season. We did not deserve to lose, but it is finished now."

City now stand seven points ahead of Villas-Boas' side, a gap the Portuguese wrote off as "nothing," given how competitive the division has proved to be this season.

"It was a good win, it has been a good week for us and I think it changes our challenge for the Premier League," he said. "Seven points in this league, with so many teams competing for the title, is nothing. There are a lot of games to be played. Manchester City have Arsenal next week, and we have Tottenham. It depends on your consistency. We put on a very good challenge against the record-breaking league leaders, so it is very gratifying."

That it should be Lampard who secured victory is ironic, of course, given that the England international has, in recent weeks, become the highest-profile victim of the Portuguese's attempts to change Chelsea's style. Lampard, though, insists he has no intention of leaving Stamford Bridge until the end of his contract in 2013 at the earliest.

"I am at my best when I play," he said. "I was in a good run of form, but I'm 33, so I understand. I want to keep doing well and playing regularly. I have got 18 months left here and I will be here for that long at least."