Manchester City boss Mark Hughes feels the air of invincibility surrounding the top four has been stripped away.

Although City were not able to capitalise on defeats by Chelsea and Liverpool yesterday when they were held to a 1-1 draw at Wigan this afternoon, it is already clear the cash-rich Blues will mount a sustained assault on the Premier League's established elite.

Third-placed Tottenham are also riding high, while Aston Villa will hope to maintain a challenge as well having got themselves into a great position last term, only to throw it away in a dismal final 10 games.

Such a disastrous finale is unlikely to happen again, which Hughes senses has led to a twitchiness amongst the high and mighty, which just makes them even more vulnerable.

"There are some good teams in the Premier League this year," said Hughes.

"There is a focus on ourselves because we have the ambition to have a good season. But the fact there is a threat to the teams who have had those top four places is adding extra pressure.

"You just sense maybe that feeling of invincibility is no longer there. Other teams think they can take points off them."

Sir Alex Ferguson mentioned it yesterday after Manchester United had endured a nervy final 15 minutes before collecting three points against Bolton.

Liverpool are the ones who presently have most to fear, although all the big clubs are having problems.

"There are two or three teams who quietly think they can get into the top four," said Hughes.

"They don't broadcast it so they keep themselves under the radar. We can't help but be one of the teams people think should be in the top four.

"We have to deal with that anyway. I just think this year has the potential to be as open as it has ever been because the top four teams will drop points.

"That has been evident at the beginning of the season and I think it will continue. It is good for the Premier League."

Although Roberto Martinez claimed Wigan were the better side, it is highly likely City would have gone on to win this fixture if Pablo Zabaleta had not been sent off for a second bookable offence 25 minutes from time.

Hughes felt Zabaleta's first-half caution was harsh. However, his second tackle - on Jason Scotland - left Alan Wiley with little alternative other than to brandish the red card.

It was Wiley's first appearance since Ferguson's infamous attack on his fitness, for which the United boss has since apologised, even if it is unlikely to prevent him being charged by the FA tomorrow.

Hughes did have a gripe, for a Maynor Figueroa tackle on Shaun Wright-Phillips which he felt was a clear penalty.

However, the City boss merely smiled after delivering his verdict.

"He was in an excellent position - he had kept up with play very well," he said.

"He made a wrong call but his positioning was excellent. Well done Mr Wiley."

A drab opening period was illuminated in stoppage time when Shay Given could only parry Hugo Rodallega's shot into the path of Charles N'Zogbia, who got in front of Wayne Bridge to slide home.

Yet, in playing time, Wigan's lead lasted seconds as City levelled through Martin Petrov at the start of the second period.

The visitors were just starting to get on top when Zabaleta was dismissed, although Latics boss Martinez was proud of his side's efforts.

"I would say the performance was well worth a victory," he said.

"Manchester City are an outstanding team with a fabulous group of players. Our performance deserved the three points."