LONDON -- One of the reasons the San Francisco 49ers are 5-2 and on a four-game winning streak is they have developed into a three-phase team.Not only are the 49ers' offense and defense playing well, but the special-teams units (particularly the coverage teams) are becoming dominant. That is crucial since the 49ers advanced to the Super Bowl with weak coverage units last season. Improving special teams was a point of emphasis in the offseason and is it working out well for the 49ers.