By David Hamill

When Chelsea swept Arsenal away just over a week ago it had many suggesting Carlo Ancelotti’s side would run away with the Premier League this year.

But as ruthless as they were at the Emirates, the Blues were allowed to play at a training game tempo and weren’t required to exert themselves. However, at Manchester City, they were pressurized, harried and asked questions they were unable to answer.

Just like their defeats at Wigan and Aston Villa earlier in the season, Chelsea conceded soft goals from set-pieces at Eastlands and it demonstrates that if you get at them you can cause serious problems.

Petr Cech is not as commanding as he used to be and was culpable in all three defeats, while ageing players like Deco and Michael Ballack will struggle in a battle.

The Blues are still in a great position in the table and are formidable opposition if teams stand off and admire them as they have the quality to destroy anyone.

And while they usually have enough resolve to grind out results in the more challenging games it’s not always certain they will come out on top.

In truth the Blues were only a penalty kick away from clinching a point but were denied by the brilliance of Shay Given, while Didier Drogba missed a chance he would expect to take late in the game.

But the overall performance and the individual errors suggest the Premier League title race is far from over and Chelsea have a lot of hard work ahead at them.

Every big four team is vulnerable so it will come down to mental strength as much as ability over the coming months to decide who are crowned champions.