Louis van Gaal has said he will solve Manchester United’s injury crisis by applying the methods that solved Arjen Robben’s fitness problems and the manager is also confident that his players will click soon.

United have five points from the opening five games and have won just once. Last Sunday the side capitulated at Leicester City, allowing four unanswered goals in 21 second-half minutes to lose 5-3.

Van Gaal has nine players injured for Saturday’s visit of West Ham United. Three of these, Chris Smalling, Phil Jones and Jonny Evans, are frontline centre-backs and Tyler Blackett, who has been given a regular chance in the position, is also unavailable due to his red card at Leicester. While Van Gaal admitted this will force him to draft in reinforcements from the under-21 squad, he is aware of the various fitness problems that have dogged Smalling, Jones and Evans during their United careers.

“I have been told [about this] and now they are confirming [it]. But I have good hopes that we shall improve in that matter because normally I don’t have any injuries,” he said, before citing the case of Robben when Van Gaal was in charge of Bayern Munich from 2009-11. “As a good example, for a player who was many times injured – Robben – he was never injured [during my reign].”

Asked precisely how he will ensure the injuries stop, Van Gaal said: “By training. By training sessions and adapting to their level. It was not only Robben but every player. And we are doing that here in the same way, only less than I have done with Bayern Munich. We have to improve the level and intensity so players can play the game.”

Van Gaal insists his methods will work even on the injury-prone Smalling, Jones and Evans. “Yes, of course,” he said. “I’m 25 years in this profession and you learn every year but you gain a philosophy in all the years and apply that.”

The defensive trio are all predominantly right-sided and Van Gaal suggested the club may have tried to sign another during the summer window. “Maybe we were in the market already in August for a right central defender. You never know. But I don’t want to discuss that with you.”

United’s disappointing results have come against some lesser teams, with Swansea City winning at Old Trafford and Burnley and Sunderland managing home draws, alongside Leicester’s victory. Van Gaal has started slowly at some of his previous clubs. In his opening season at Bayern, his side were seventh after 13 matches yet went on to win the title. In 1998-99 Barcelona were 10th after 14 games and won La Liga.

“We give a lot of information [to the players] and you have to work out that information,” he said. “I have said that before. There shall be a moment in the season when this information is too much – maybe at this moment it is too much for the players, but I have already said it’s more [about] advice. “You have to be yourself, you have your own identity. But that’s very difficult because we are starting with a new team, a new relationship between players, so that’s why it needs time. But I don’t want to say that all the time because all the fans are very tired of hearing that sentence.”

Van Gaal said initially that his squad would need three months to click and from 26 October, which is around that mark, United face Chelsea, Manchester City and Arsenal in three of their next four games. The Dutchman is optimistic the players will be comfortable with his approach by then. “You never know. I hope it is like that. In all my former clubs it has worked like that,” said the 63-year-old, before citing Sunday’s reverse. “It did surprise me that from leading 3-1 we lost 3-5. I have a lot of experience but I never had an experience of five goals against.”

He added regarding his defence: “My concern is never the age or the experience. My concern is the profile and you have to fit in the profile and I don’t want to buy players who don’t. There are a lot of defenders in the world but I don’t want to buy any defender. I want to buy defenders who fit in the profile.

“That’s what I like and age is not so important. I played with the Dutch national team, with Bruno Martins Indi and Stefan de Vrij – both 22. Never played in the Premier League or abroad. Now they are abroad because of the World Cup. I played with Ron Vlaar and he plays with Aston Villa. That was my defence and we did very well at the World Cup and until Leicester we [United] had only three goals against in spite of the fact we were not playing so well.

“Our defensive organisation was very good and also in the United States [in pre-season] it was very good. But now you want to make everything negative, but that’s not true. We scored three goals, Van Persie had a chance to make it four but then it was over.”