And Deco insists that is it Chelsea's dominance up front that will help them beat Sir Alex Ferguson's side at Stamford Bridge on Sunday to move five points clear at the top of the table.
Related ArticlesChelsea sell stadium naming rightsChelsea v Manchester United: match previewGourlay's Chelsea pledgeDebate: Drogba v RooneyBosingwa knee surgery blowAtkinson to referee Chelsea v Manchester United"The big difference between us and United is in attack. Drogba is enjoying a spectacular moment in his career and is superior to the front-line of United," Deco told the Sun.
"For me, Didi will be the key - the star of the match, for sure."
Hopeful that defeat will damage United's confidence for the remainder of the season, having only recently lost to Liverpool, Deco added: "This match has a four-point value, an extra one for the blow to United's morale because they also failed to beat Liverpool.
"If they fail in London they will need to think very much about things in the following days. Victories in classic matches like this always have enormous value.
"For Chelsea to begin November with a five-point advantage over United will be sensational."
Meanwhile, Chelsea have opened contract talks with Joe Cole and look likely to agree terms on a deal which would see the midfielder stay at Stamford Bridge until 2014.
Talking to Chelsea TV, new chief executive Ron Gourlay said: "Joe's looking to negotiate his new contract for the next four to five years. That process has started and Joe has made it very, very clear he wants to stay with the football club.
"I am sure over the coming months we will be able to work something out."