Rio Ferdinand says Wayne Rooney is producing his best form for England on a consistent basis as he prepares to win his 50th international cap.Rooney has had an up-and-down career for his country since making a massive impact during the Euro 2004 finals, where he was injured in the quarter-finals against host nation Portugal.He even went three and a half years after that tournament before scoring his next competitive goal for England - against Estonia in October 2007.But Ferdinand now sees Rooney producing the goods on a regular basis and he has scored seven times in his last four internationals.The centre-back, who has recovered from a back problem to face Ukraine, said: "Wayne is an integral member of our squad. He is beginning to play consistently well for England and he is improving in the right way."I wasn't involved on Saturday (against Slovakia) and had a better look at how individuals are playing and Wayne was probably our best player by a distance at the weekend."He was doing the things that the manager asked of him, picking the ball up in dangerous areas and putting people in on goal and getting chances on goal, and he got a couple for himself."He is implementing what the manager is trying to get out of team and the more players we have doing that, the better chance we have."Ferdinand knows it is vital for Rooney and England's other key performers to stay fit if they are to challenge for future glory.The Manchester United star said: "People say England might have won Euro 2004 had Wayne stayed fit and he played well in the games. There are a lot of ifs and buts."But, for the future, it is vital that we keep everyone fit for the qualifying campaign and, if we do that, we will have a much better chance of qualifying."The good thing is that when Wayne is confident and playing well, there are not many better sights in football. He is vital and if he is doing the right things, it is only good for us."To see that hunger and desire in him to be a better player only bodes well for England's future - and he is still only 23."Ferdinand claimed the England players know they have to produce performances to stay part of Capello's plans and that reputations will count for little.He said: "This team is very focused on what we want to achieve and the manager has made it very plain and clear what he wants from us as individuals and as a team."If we don't produce or do what he is asking, then we know we won't be in the next squad. You have got to be on your toes and be doing what he is asking of you."It is about form and fitness and that is great. That is the way it is at most clubs and is the way it should be at international level."There is no room for egos and reputations. This manager has won a lot of things in his career and he hasn't done that by putting an arm around a player just because they have got a big reputation."He has done it along the lines of 'this is the right man for my team', and that is good."England will consolidate their position at the top of the group if they chalk up a fifth successive win at the expense of Ukraine but Ferdinand insists nothing is being taken for granted.He said: "We won't have one foot in the door of the finals if we win. If we win this game, we can look to the next game."But, if you start looking ahead and taking your eye off the coming games, you lose focus and lose sight of where you want to be."We have to keep performing in each game otherwise it can quickly turn from a positive situation into a negative one. There won't be any room for complacency, that is for sure."