Fergie wary of Blues threat

// A bit of a hack but it works// The article snippet is wrapped onto a second line, even when #article-sub is emptyif( $("div#article-sub").children().length == 0 ) {$("div#article-sub").remove();} Sir Alex Ferguson believes Chelsea are the side most likely to challenge Manchester United for top spot in the Premier League this season. Manchester United have claimed the title for the past three seasons and have made an encouraging start to the defence of their latest crown.Chelsea are the only side above them and will be looking to stretch their lead to five points in Sunday's eagerly-anticipated clash between the two at Stamford Bridge, live on Sky Sports 1 and HD1.The likes of Arsenal and Manchester City have also impressed during the early part of the campaign but Ferguson expects Carlo Ancelotti's Blues to provide the main threat to United. "It's looking that way," he told Inside United. "It seems they will be the ones to get in front of."Change of systemAncelotti has introduced a diamond formation at Chelsea to get the best out of Didier Drogba and Nicolas Anelka and Ferguson admits they are a more formidable outfit. "It is a very experienced team," said the Red Devils manager."I said last year it is a team that can only improve results by the system they adopt."Ancelotti has brought in the system he used at AC Milan, with the diamond in the middle of the pitch."It is hard to break down when you get into their third because they have got bodies compacted into the central area of the pitch."Jose Mourinho played one up and five in the middle of the park - that also made Chelsea very difficult to beat, but in a different way to what Ancelotti is doing."Ancelotti's got the two strikers, and that is a major change compared to Luiz Felipe Scolari and Claudio Ranieri."

Source: SKY_Sports