The Spaniard said: "Yes, the money people are asking is crazy. I hear, for example, that people at Seville are asking for 41m euros for Daniel Alves. That is a lot.
"The market is crazy, but you must pay good money for good players.
"The money for Johnson is OK. He is English, an international with quality and he is worth the money.
"He is a very good attacking player. If you try to buy a winger it can be £50m to £60m at current prices, but Johnson as an offensive full-back can give us more options.
"He can be good for us, especially when we are at home and teams are defending against us. Going forward he will give us something different, something special. He is a good addition for us."