When it was announced that Jose Mourinho was to be the new Chelsea manager, many people in football likened his era to be like master and apprentice, with Sir Alex Ferguson being his guiding light. To his credit, Mourinho has always made clear his deep respect and affection for Ferguson. So it is an ironic twist that it is actually one of Mourinho`s earliest tactical innovations that has been resurrected by Sir Alex in his attempt to wrest back the title from Manchester City.

There were a few eyebrows raised when United made their first moves for Kagawa, with those in the UK media questioning where another midfielder would play. When it became clear that United were in serious contention for Van Persie`s signature, those media `experts` were even more flummoxed. There were questions as to why United were`nt looking for defensive replacements, however, that question was answered by another signing in the form of Alex Buttner, a defender who was two-footed and could play either left or right back, although he preferred left back. That covered the left back position, where Patrice Evra was showing signs of deterioration over the last season. Questions about the wisdom of signing a relatively unknown player in this country, were assuaged when it transpired that he was already a full international in the Netherlands team, no mean feat for any footballer.

Of course, all of these moves had to be justified, so Sir Alex started on his master plan. It transpires that he has now started using the diamond shape formation, and that is why he had to get certain players in, and move others into new positions. He now had his four players at each point of the diamond in midfield. He also had cover for each position. One of the positions he needed to cover was the forward point of the diamond, where he had Rooney, just behind Van Persie and/or Welbeck up front. That is where Kagawa comes into the equation. He can play that position with ease, having done a similar job at his previous club, Dortmund.

There have been one or two upsets using this new formation, mainly due to unforseen injuries. The game against Tottenham got away from United due to an outstanding performance from Gareth Bale. Unfortunately, both Evra on the left and Rafael on the right did not seem to understand their duties and were too often left upfield leaving just Ferdinand and Evans to face tow, sometimes three pacy forwards.

Having taken that on the chin, Sir Alex has persevered with this system and it is now paying dividends as the players learn how to play it properly. Another advantage is that United can always slip back to 4-4-2 or use the fullbacks as wing backs if needed.

Apart from the Tottemham game, it seems that the master has learned from the apprentice and Sir Alex`s `secret weapon`, borrowed from Mourinho,  will catch out most of their opponents this season.