Louis van Gaal, whose Manchester United side host Chelsea on Sunday, said he has an “iron shield” that prevents him from being ruffled by José Mourinho’s mind games. The Chelsea manager is notorious for upsetting opposing managers yet Van Gaal is clear the man who was his protege when the Dutchman was in charge of Barcelona from 1997-2000 can never upset him.

“Maybe now you know that I am always a controversial person and a lot of media has written about that,” the United manager said. “I’m [made] from a little bit of iron – so [I have] a shield, an iron shield.”

Pressed if anything can penetrate this armoury, Van Gaal said: “No. Because I think everybody can write or speak about me – I cannot change that. It took me a long time to understand that but I cannot change what you are writing about me. So I have learnt not to react and believe in myself, my players, my staff and that is important.”

Van Gaal offered a picture of a more tender Mourinho than is familiar from his public persona. “We hardly speak to each other [at the moment]. Sometimes we SMS but when we see each other we feel the warmth between us and our families so that’s nice,” he said. “He is a very modest and emotional human being.”

Regarding whether Víctor Valdés, the former Barcelona goalkeeper who is training at United, might be offered a contract Van Gaal said: “Manchester United always has their eyes open.”